This section focuses on procedures related to inspection. Some topics, for example note-taking, may also apply more generally to evidence collection.


Preliminary research can help you get the most out of your site visit. Inquiries might include:

  • applicable rules for the site including zoning, scheduled items, and other site features, characteristics or limitations

  • building plans if the matter relates to built work, so a general comparison can be made on-site between what has been built and what has been approved

  • any resource consents and their conditions

  • compliance history on file for the site

  • aerial photos

  • possible witnesses

  • collecting any information that may assist in the preparation of a scene diagram.

Investigation and collecting evidence onsite

Once on-site, an enforcement officer may collate information and evidence through a variety of means including:

  • preparing a scene diagram

  • sampling

  • note taking

  • photographs .

Checklists can be useful in guiding the investigation and collecting evidence. They can serve as prompts to guide procedures and remind officers of:

  • other possible lines of inquiry or investigation methods

  • witnesses who may need to be interviewed

  • evidence which may need to be photographed.

Scene diagrams

A scene diagram is a way of illustrating the evidence you are giving in court. Its accuracy might be challenged, so prepare a drawing at the scene first. This will give you confidence about the details and help refresh your memory if necessary.

While the diagram should be kept simple, it might include the following features:

  • an indicator for north

  • key buildings and boundaries

  • the location of the offending or causative actions/omissions

  • locations and numbers of any samples collected

  • reference points to accurately place any photograph taken or a more detailed diagram made at the scene

  • the area where any effects occurred and arrows showing any movements of those effects

  • the location of, and identifiers for affected people, animals and objects within the effects areas

  • incident factors including contributors such as wind direction for spray drift; and impeders such as natural or artificial shelter belts for spray drift.

An effective method is to use acetate sheets for investigations where features of the land or land use are important. Overlay these on land-base maps of the area, which may incorporate, for example, roads and infrastructure, topography, aerial photographs, property boundaries, or zoning. If relevant your sketch should include any variations to the underlying land-base information.

Finalising a scene diagram on a computer produces the best result. A few arrows and labels pointing to key features can be helpful.


Measurements can sometimes be material facts in an offence. Sometimes the measurements that need to be taken do not relate to a specific object or location. What needs to be determined is the effects of an activity on a wider area or population. If so, then choices must be made about what is sampled for measurement, to provide an indication of the big picture. For economic and practical reasons, the number of samples must be limited, but the investigating officer must ensure that they are as representative as possible.

For example, random sampling either across a broad population or within target strata (categories or groupings) is generally the most representative method. In some cases, randomness can be approximated by walk-through sampling of an affected area, so long as a large number of locations are used. Be mindful that certain features of an area that are likely to capture attention may bias the sample.

Where measurements relate to a discharge, it may be important to determine the path of the contaminant and restrict your sample to it. This approach will provide a more accurate picture of the damage done. One way of determining the path is to work backwards from the location of the complaint to the site of discharge, taking into account the mechanics or methods of discharge and any external factors such as wind direction.

You should adapt sample collection to the type of material being sampled. The method should be scientifically acceptable. For example:

  • Vegetation and water samples provide the best indication of spray drift.

  • Any soil samples should be taken from exposed areas, scraped from the surface only.

  • Hard-surface samples of contaminants can be collected by wiping the surface with a clean tissue and placing the tissue in a clean press-seal bag. An unused tissue from the same batch should be submitted in a separate sample bag for comparison (the 'control ').

All other possible causes must be considered and excluded. For example:

  • Plant damage, human health and animal symptoms may not have been caused by an agrichemical, but by stress, disease or other factors.

  • Even where a herbicide is the cause, other applications nearby, even some weeks beforehand, could have caused the damage. Volatile agrichemicals are capable of travelling kilometres off target, so consider interviewing neighbours.

  • There may be more than one point of discharge, each with its own operator and particular factors. Samples should be collected from these other sources to establish their effect on the receiving environment.

  • The fact that a discharge pipe is located on a particular property does not necessarily mean the occupier of that property is causing the offence.

Use laboratories with registered quality assurance procedures. Make sure that the laboratory completes a chain of custody form to ensure the sample is not confused with another sample and is kept secure, so there is no possibility of the sample being tampered with or cross-contaminated.

Technical instruments

Enforcement officers are likely to use a variety of technical instruments in collecting samples and in carrying out field measurements. The admissibility of data generated by mechanical or computerised instruments is subject to the EA. To be able to admit evidence collected by the use of an instrument it is necessary to show the following:

  • The instrument was used by someone qualified to use it.

  • There was correct operation of the instrument, and it was in good condition for accurate work. It may be necessary to produce the manufacturer's specifications for the instrument and give evidence that the instrument was regularly maintained and/or calibrated in accordance with the manufacturer’s specifications or standard analytical methods or procedures.

  • If the instrument is complex and not in common daily usage, evidence must show that the instrument was constructed and/or programmed on scientific principles, and is accepted as dependable for its purpose by the profession concerned in that branch of science or its related field. This sort of evidence can only be given by an expert.


Some types of samples need to be dealt with quickly to avoid degradation and maintain their evidential integrity. Some samples may need to be frozen or stored in airtight containers until decisions are made as to whether, for example, the sample should be sent to a laboratory for analysis.

Sampling may need to be repeated to take account of any lag in time until the full extent of damage occurs.

Witness evidence should be taken as soon as possible after an incident, so the events are fresh in the person’s mind. Recorded statements will assist the witness in preparation for court later. The leads gained are likely to be more accurate immediately after an incident.

Chain of custody

The chain of custody practice ensures that you know, and can account for, exactly what happened to a sample from the time an enforcement officer took it from its original site until the time an expert (or the court) can assess it.

The practice avoids the risk that evidence could be changed, whether deliberately or mistakenly (eg, by cross-contamination of samples), to bear more weight against the defendant than merited. For this reason, an identifiable person must always have the physical custody of a piece of evidence, and record the history of what the evidence was exposed to and which might affect its evidential characteristics (eg, utensils, gloves, or containers).

The chain of custody is particularly important when a number of people are involved in handling the sample. This could include a company contracted to take the sample, and a laboratory to analyse it. When the sample is not with you, you must be able to account for its location (eg, "I placed the sample in a chilly bin in the local authority vehicle and I locked the vehicle").

In practice, the chain of custody means the following:

  • The officer will take charge of a piece of evidence, document its collection, and hand it over to a person/system for secure storage.

  • Every transaction between the collection of the evidence and its appearance in court should be documented chronologically in order.

  • Documentation should include the conditions under which the evidence is gathered, the identity of all evidence handlers, duration of evidence custody, security conditions while handling or storing the evidence, and the manner in which evidence is transferred (see RMA Enforcement Manual Forms and Checklists - Chain of custody). 

Examples of measures taken to secure the chain of custody include:

  • another person to assist with collection, storage, and delivery (to corroborate your account)

  • photographs of samples collected to corroborate your account (although scenes could be falsely duplicated)

  • fresh gloves, containers or bags for each sample; well-sealed containers; and clean equipment used for taking samples, to avoid cross-contamination

  • storing samples to avoid degradation from light

  • labelling and recording samples before moving between sites (or to other spaces within sites when location may be a significant factor in proving the offence), to avoid any possibility of confusion as to where the samples came from

  • using a seal on the container large enough for a signature, and name, and incorporating a tape that cannot be removed without trace (sealing tape identified clearly as the property of the local authority is more suitable than blank tape)

  • securing samples in locked areas with controlled access at all times (including agreed secure procedures with any laboratory)

  • securing all courier receipts, or receipts from the laboratory (PDF, 16 KB) , as evidence of the chain of custody (lost receipts can only be compensated for by the records of courier companies; these take time to retrieve).

Four relevant cases relating to the taking of samples and the chain of custody are:

  • Northland Regional Council v Northland Port Corporation (NZ) Ltd and others [1996] CRN 5088011428-447, 527-528, 532-533

  • Northland Regional Council v Juken Nissho Ltd [1998] CRN 7029003709, 7029003874 and 7029004299

  • Wellington Regional Council v 0 'Rourke and Cremen [1993] CRN 3035007074-76

  • Canterbury Regional Council v Pacific Marine Limited [2001] (RN0009026633)

Note taking

Notes from inspections and interviews (whether formal, on-site or on the phone) are essential for the following reasons:

  • The notes will form the basis for briefs of evidence (yours, and other witnesses ') that will be prepared for any hearing or affidavits for matters dealt with ex parte (applicant alone, no other parties) or on the papers.

  • The notes can be referred to by the note-taker when giving evidence about things observed or admissions heard, to refresh his or her memory in a prosecution, so long as the note was taken at the time of the incident or admission, or as soon as possible thereafter.

  • Local authorities have six months after an incident to lay charges but it may take another 6 to 12 months to obtain a hearing date. Notes are necessary to remember the details of what happened, once the matter is in court.

Refreshing memory from notes

The elements of an offence are sometimes multiple and technical, involving such things as dimensions, gradients, materials, or species. They sometimes also capture a concept where there is room for personal interpretation, like what is 'offensive ' or 'obstructive '. The details are very important, and 6-12 months after the event when you are in a court room being cross-examined, there is a good chance you will not be able to clearly recall all of them.

Fortunately, the law allows witnesses to refresh their memory from written documents, with the prior leave of the judge and after the documents have been shown to all the other parties: s90(4),(5) of the EA. The document must have been made or adopted at a time when the witness's memory was fresh. There are no hard and fast rules on how soon after an inspection the documents must be made. What is acceptable depends on the circumstances: making a note a few hours after a site visit may usually be acceptable, but in some cases this could result in concerns about reliability. For example if other similar sites were visited or other detailed inquiries undertaken in the intervening time between an inspection and preparing the written record, there could be mistakes made.

If notes are rewritten or typed, always keep or scan the original hand-written notes. These notes are the contemporaneous record that you will rely on in court to refresh your memory.

Taking photographs

A photograph can depict facts important to determining whether an offence has occurred, such as the damage done by the offence occurring. Photos are advantageous because they:

  • often provide evidence that is hard to dispute: "a picture is worth a thousand words"

  • are not subject to changed meanings each time they are challenged

  • are less likely to miss important details (or lose supporting information) than may occur in note-taking

  • can depict a crime scene in an easily absorbed way, helping the court to understand the facts of the case

  • can provide good evidence as to the scale of the offence - showing the risk, damage or other issue which the legislation seeks to address. These matters, if not directly elements of the offence, will usually be visually inseparable from admissible evidence. They will assist the court by illuminating the sentencing submissions made later.

The key benefits of photographs should guide the investigator in taking them:

  • Facts in issue: know the elements of your offence, and if the opportunity exists, ensure you have photographs of places and things that depict those elements. For example: if the offence is the removal of protected vegetation of specified species and size within a riparian margin, take photographs close enough to assist in identification of species, others that depict the size of felled trees or of the remaining stumps by way of a measuring stick or tape, and also show the location of removed trees in relation to the waterway.

  • Depiction of crime scene: overview photographs will help establish the scene in the court’s mind. Ensure they include parts of the scene that depict where the evidence lies, so you can then 'zoom in' with detail shots later. Consider the angles that photographs can be taken from to best show what happened, or the circumstances of the incident.

  • Significance of an offence: camera angles, close-ups and other ways of capturing details of the offending may assist. Also comparative photographs may help if they exist, for example showing a site where damage occurred before and after the offending.

  • Take photographs that will help you remember your experience of the scene. In court, they will refresh your memory and help you deal with questions.

Photographs are powerful, but without some explanation their value is limited. They are best produced at court with an explanation both of what is in them and of the circumstances in which they were taken. It is a good idea to record this information in a notebook at the time; the date and location of the evidence found and photographed may be critical.

It is better to take too many photographs than too few. It may not be possible to go back later and take more photographs if the scene has changed and evidence has been removed.

Section 332 of the RMA does not specifically allow enforcement officers to take photographs, although in most cases the owner or occupier does not object to photographs being taken. In Waitakere City Council v Gordon [1999] MA 99/99, the District Court Judge commented that a warrant under s334 of the RMA would always be a wise precaution. Compare this to An Application by Waikato Regional Council v Wellington [2002] A226/02, where the Environment Court Judge considered the Waitakere case and stated that photographs are an aid for recalling what the officer has seen and are part and parcel of recording an inspection.