Acts Interpretation Act 1901




The following is a simplified outline of this Act:


This Act is like a dictionary and manual to use when reading and interpreting Commonwealth Acts and instruments made under Commonwealth Acts.

The definitions and many of the interpretation rules are aimed at making Commonwealth legislation shorter, less complex and more consistent in operation.

A provision of this Act is subject to a contrary intention in other Commonwealth legislation.


Part 1 provides that this Act applies to all Acts. This Act also applies to legislative instruments, notifiable instruments and other instruments made under an Act (see subsection 13(1) of the Legislation Act 2003 and subsection 46(1) of this Act).

Part 2 contains definitions that apply across all Commonwealth legislation (for example, Australian citizen , business day , document and month ).

Part 3 deals with the commencement of Commonwealth Acts. For example, section 4 allows certain powers to be exercised (like the making of appointments) between the enactment and commencement of an Act.

Part 4 deals with the amendment, repeal and expiry of Commonwealth legislation. For example, section 7 provides that the repeal of an Act does not affect any rights accrued under the Act, or any legal proceedings instituted, before the repeal.

Part 5 contains various rules for interpreting Commonwealth legislation, including:

  • (a) section 15A (about interpreting an Act subject to the Constitution); and
  • (b) section 15AA (which provides for interpreting an Act in a way that best achieves the purpose or object of the Act); and
  • (c) section 15AB (about using material that is not part of an Act (like explanatory memorandums and second reading speeches) in interpreting an Act); and
  • (d) sections 19 to 20 (which deal generally with references to Ministers and Departments in Acts, with the effect of machinery of government changes on references to Ministers and Departments and other authorities in Acts and Commonwealth agreements, and with the validity of acts done by Ministers).
  • Part 6 deals with the service of documents on persons.

    Part 7 contains rules about exercising powers and performing functions and duties under Commonwealth legislation, including:

  • (a) subsection 33(3) (which provides that a power to make an instrument includes the power to vary or revoke the instrument); and
  • (b) section 33A (about acting appointments); and
  • (c) sections 34AA , 34AB and 34A (about delegating powers, functions and duties).
  • Part 8 deals with the calculation of distance, time and age.

    Part 9 deals with the citation of Acts.

    Part 10 deals with instruments other than legislative instruments or notifiable instruments. For example, it provides that this Act applies to those instruments and that expressions in those instruments have the same meaning as in the enabling legislation.

    Part 11 contains a regulation-making power.

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