Immunity from prosecution for authorised persons
Section 18(2) of the RMA provides immunity from prosecution for an activity that is undertaken in accordance with s330. Therefore, the immunity will not apply in any of the following circumstances:
the work is not carried out by authorised persons (as described in s330)
the circumstances are not deemed to be an emergency
the works are inappropriate in type or scale for addressing the emergency only.
Because a local authority is responsible for enforcing its plans, it will want to scrutinise decisions relying on s330 to undertake activities without obtaining resource consent. It will want to be convinced that emergency powers apply. However, it cannot do so unless it is advised that the powers have been exercised.
While s330A requires any person who has relied on s330 to advise the consent authority of an emergency work (and to apply for consent if effects are on-going), there is uncertainty as to the consequences of that person not complying with s330A. Immunity from prosecution under s18 does not depend on compliance with s330A. Non-compliance with s330A is not an offence under s338. Therefore it is generally best for the enforcing authority to issue an abatement notice (or seek an interim enforcement order) to require an application for consent.
For this reason, anyone exercising powers under s330 of the RMA should:
maintain records of any delegations or contracts that relate to the types of work that may be carried out as an emergency work
consult with the consent authority immediately before undertaking any emergency works where this is possible in order to gauge the consent authority's opinion on whether the situation constitutes an emergency, and
record all key steps and factors in decision-making.
There is conflicting case law on who needs to establish whether the s18 immunity applies. One line of cases suggests that s330 contains elements which are difficult for the prosecution to prove, or which may be within the knowledge of the defendant alone. Therefore placing the onus on the prosecution may make it hard to prove that the immunity does not exist. The other cases suggest that the onus should be on the prosecution, because s330 is intended to confer express rights and powers. Unlike prosecutions for breaches of restrictions, the defendant should not suffer the onus when expressly given powers (and the immunity that attaches to their use). Refer to the following cases for a discussion of these points Southland Regional Council v Invercargill City Council  CRN 6025006200 and 6855 and Canterbury Regional Council v Doug Hood Ltd and Another  CRN 7076006424 .
In either case, a person or body acting reasonably and responsibly throughout, and maintaining records of such, would be in a better position of avoiding a charge, or defending against prosecution if charged.