An Act to amend the War Crimes Act 1945

5. Sections 3 to 14, inclusive, of the Principal Act are repealed and the following section and Parts are substituted:
...

"(2) In determining for the purposes of subsection (1) whether or not an act
was, under the law in force at a particular time in a part of Australia, an
offence of a particular kind, regard shall be had to any defence under that
law that could have been established in a proceeding for the offence."

"(3) An act is a serious crime if:

(a) it was done at a particular time outside Australia; and

(b) the law in force at that time in some part of Australia was such that the act would, had it been done at that time in that part, be a serious crime by virtue of subsection (1)."

Article 22
Nullum crimen sine lege
1. A person shall not be criminally responsible under this Statute unless the conduct in question constitutes, at the time it takes place, a crime within the jurisdiction of the Court.
2. The definition of a crime shall be strictly construed and shall not be extended by analogy. In case of ambiguity, the definition shall be interpreted in favour of the person being investigated, prosecuted or convicted.
3. This article shall not affect the characterization of any conduct as criminal under international law independently of this Statute.