Nulla poena sine lege

Australia

Australia - Mutual Assistance in Criminal Matters Act No. 85 1987 (2018)

Part I—Preliminary
8 Refusal of assistance
(2) A request by a foreign country for assistance under this Act may be refused if, in the opinion of the Attorney General:
(b) both of the following subparagraphs are satisfied:
(i) the request relates to a foreign order in relation to an offence;
(ii) an act or omission constituting the offence, had the act or omission occurred in Australia, would not have constituted an offence against Australian law at the time at which the request was received; or

Rome Statute

Article 23 Nulla poena sine lege

A person convicted by the Court may be punished only in accordance with this Statute.