History of the Section

This provision is modelled on article 15(1) of the ICCPR.

Comparative rights table


27. Retrospective criminal laws

Section 27(2):

A penalty must not be imposed on any person for a criminal offence that is greater than the penalty that applied to the offence at the time when it was committed.

Section 27(3):

If a penalty for an offence is reduced after a person committed the offence but before the person is sentenced for that offence, that person is eligible for the reduced penalty.


Article 15:

1. No one shall be held guilty of any criminal offence on account of any act or omission which did not constitute a criminal offence, under national or international law, at the time when it was committed. Nor shall a heavier penalty be imposed than the one that was applicable at the time when the criminal offence was committed. If, subsequent to the commission of the offence, provision is made by law for the imposition of the lighter penalty, the offender shall benefit thereby.

2. Nothing in this article shall prejudice the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognized by the community of nations.

ACT: Human Rights Act 2004

Section 25(1).
Section 25(2).

S Africa: Constitution of the republic of South Africa 1996 Chapter 2
Section 35 (3)(l).
Section 35 (3)(n).
UK: Human Rights Act 1998
Schedule 1, art. 7.
Canada: Canadian Charter of Rights and freedoms

Section 11(g).

New Zealand: New Zealand Bill of Rights Act 1990

Section 26(1)