Section 49 of the Australian Constitution provides:
The powers, privileges, and immunities of the Senate and of the House of Representatives, and of the members and the committees of each House, shall be such as are declared by the Parliament, and until declared shall be those of the Commons House of Parliament of the United Kingdom, and of its members and committees, at the establishment of the Commonwealth.
The effect of this provision is to incorporate into the constitutional law of Australia a branch of the common and statutory law of the United Kingdom as it existed in 1901, and to empower the Commonwealth Parliament to change that law in Australia by statute. The framers of the Australian Constitution, unlike their United States counterparts, did not attempt to fix the law of parliamentary privilege in the Constitution, although, as will be seen, the law in the two federations has remained substantially the same. Even in Australia, notwithstanding the power to legislate in section 49, some aspects of that law may be constitutionally entrenched as essential to a legislature, and therefore not amenable to change by statute.
The power of the Parliament to legislate under section 49 was employed by the passage of the Parliamentary Privileges Act 1987. The powers, privileges and immunities attaching to the two Houses under the section and the statute are extensive. The principal privilege, or immunity, is the freedom of parliamentary debates and proceedings from question and impeachment in the courts, the best known effect of which is that members of Parliament cannot be sued or prosecuted for anything they say in debate in the Houses. The principal powers are the power to conduct inquiries (including by compelling the attendance of witnesses, the giving of evidence and the production of documents), and to adjudge and punish contempts of the Houses.
The Parliamentary Privileges Act 1987 arose partly from a critical examination of parliamentary privilege as it existed under section 49. In 1984 a joint select committee of the Houses, after a comprehensive review of the subject, recommended a number of changes to the law and to the practices of the Houses in matters of privilege, partly based on earlier British reports and partly based on practices adopted by the Senate.
The 1987 Act made the changes to the law recommended by the select committee, but with a number of significant modifications. The bill for the Act was introduced into the Senate by the President, the first such bill so introduced, in circumstances described below. In February 1988 the Senate passed resolutions (known as the Privilege Resolutions) making the suggested changes in its practices, again with modifications. The House of Representatives has not generally adopted the resolutions. The changes made by the Act and the resolutions are outlined in this chapter in relation to the particular aspects of the law and practice affected.