[31.1] Australia’s international obligations are not enforceable through legal action by a person in Australia unless those obligations are incorporated into domestic legislation. If a statute does incorporate all or part of an international agreement, then, subject to a contrary intention in the statute, it is a principle of interpretation that the words in the statute are presumed to bear the same meaning as they do in the international agreement. However, even where a statute does not incorporate text from an international agreement, Australia’s international obligations may still influence the interpretation of domestic legislation. A long-established common law principle provides that, in cases of ambiguity, a construction of a statute that is consistent with Australia’s international obligations should be preferred to a construction that is not. This refers to Australia’s obligations at the time of enactment of the domestic legislation.

The chapter focuses on the distinction between treaties and other kinds of international instruments. It addresses issues such as why it is necessary to distinguish between treaties and other kinds of international instruments, and what can go wrong when a State or an IO fails to do so. It identifies other kinds of international instruments that are not treaties, their binding status, different scenarios in which it may be difficult to differentiate such instruments and how to overcome such situations. The chapter also offers some suggestions on handling treaties and other kinds of international instruments.