Acts Interpretation Act 1901 - Relationship With The Common Law

Relationship With The Common Law

When first enacted, the Act codified the common law in some cases. For example, there is a presumption at common law that parliament intends its legislation to operate only on persons and matters within its territory; the Acts Interpretation Act 1901 (Cth) repeated that presumption at section 21 (b). If an act was silent on the question, then s. 21 (b) operated to confine the act in its territorial reach. However, parliament may override the presumption and the section to give extraterritorial operation to the enactment by express words or "necessary implication".

In other cases, the Act reversed the common law. For example, there was a common law rule that, when interpreting statutes, courts could not consider "extrinsic material" such as a Minister's second reading speech made when the statute was before parliament. The Act, by s.15AB reversed this rule, giving courts access to a wide range of material which would otherwise have been excluded.

Where there are conflicting common law rules, the Act sometimes gives preference to one approach. For example, there is sometimes seen to be a conflict between a "literal" and "purposive" reading of statutes; by s. 15AA, the Act mandates a purposive approach.