The interpretation of Acts

Construction of Acts subject to the Constitution

Every Act must be read and construed subject to the Constitution, and so as not to exceed the legislative power of the Commonwealth.[517] In some circumstances an Act may be read down or read as if it did not contain any invalid provisions, so that it may be given effect to the extent that it is not in excess of the power of the Commonwealth.[518]

Regard to purpose or object of Act

In interpreting a provision of an Act, an interpretation that would best achieve the purpose or object of the Act, whether expressly stated in the Act or not, is to be preferred.[519] The purpose of an Act may be stated in an objects clause, its long title and, if one exists, the preamble. A preamble does not have separate legislative effect, but may be used for clarification if the meaning of a section is unclear.

Use of extrinsic material in the interpretation of an Act

If any material not forming part of an Act is capable of assisting in the construction of a provision of the Act, consideration may be given to the material to confirm that the meaning of the provision is the ordinary meaning conveyed by the text, or to determine the meaning of the provision when the provision is ambiguous or obscure or the ordinary meaning conveyed by the text leads to a result that is manifestly absurd or unreasonable.

Material that may be considered in the interpretation of a provision of an Act includes:

• all matters not forming part of the Act that are set out in the document containing the text of the Act as printed;
• any relevant report of a Royal Commission, Law Reform Commission, committee of inquiry or similar body that was laid before either House before the provision was enacted;
• any relevant report of a parliamentary committee presented before the provision was enacted;
• any treaty or other international agreement referred to in the Act;
• any explanatory memorandum relating to the bill containing the provision, or any other relevant document, that was laid before, or furnished to the members of, either House by a Minister before the provision was enacted;
• a Minister’s second reading speech on the bill containing the provision;
• any document that is declared by the Act to be a relevant document;[520] and
• any relevant material in the Journals of the Senate, the Votes and Proceedings of the House of Representatives or in any official record of parliamentary debates.

In determining whether consideration should be given to extrinsic material, or in considering the weight to be given to any such material, regard shall be had to the desirability of persons being able to rely on the ordinary meaning conveyed by the text of the provision, taking into account its context and the purpose or object underlying the Act, and to the need to avoid prolonging legal or other proceedings without compensating advantage.[521]