This is a single section from Chapter 12. Read the full chapter here.

Does the legislation have direct retrospective effect?

Legislation should not have retrospective effect.

The starting point is that legislation should not have retrospective effect. It should not interfere with accrued rights and duties.

Legislation might have direct retrospective effect if it:

  • applies to an event or action that has already taken place;
  • prevents a person from relying on a right or defence that existed at the time the person undertook the conduct that the right or defence related to; or
  • punishes a person or imposes a burden or an obligation in respect of past conduct.

A person should not be made criminally liable for past actions that were not prohibited at the time of commission. Section 26(1) of NZBORA provides that no one is liable to conviction for any act that was not an offence at the time it occurred. If the penalty attaching to an offence is increased between commission and conviction, the lesser penalty should also apply.

Retrospective legislation might, however, be appropriate if it is intended to:

  • be entirely to the benefit of those affected;
  • validate matters generally understood and intended to be lawful, but that are, in fact, unlawful as a result of a technical error;
  • decriminalise conduct (see for example, section 7 of the Homosexual Law Reform Act 1986);
  • address a matter that is essential to public safety;
  • provide certainty as a result of litigation (discussed in more detail in 12.2); or
  • in limited circumstances, make changes to tax law or other budgetary legislation.

If direct retrospective effect is intended, this must be clearly stated in the legislation and be capable of justification. If it is not expressly stated, there is a risk the courts will apply the presumption that legislation does not have retrospective effect.

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