The law-making powers of the Commonwealth and the States are extensive but they are not absolute. The drafters of the Constitution included several sections and clauses that act as a constraint on the power of both levels of government. Restrictions on Commonwealth power are particularly important. Without them the Federal parliament might come to acquire or exercise excessive power; this would lead to an imbalanced federalism and Federal domination of the States. Some of the constitutional constraints on government power also serve as a protection of individual rights.
Two significant restrictions on Commonwealth power can be found in Section 99 and Section 116 of the Australian Constitution:
Section 99. “The Commonwealth shall not, by any law or regulation of trade, commerce, or revenue, give preference to one State or any part thereof over another State or any part thereof.” This means that all Federal legislation must apply equally to all six States. There can be no bias or discrimination in Federal laws as they apply to States. There is consequently no Commonwealth law that applies to only one State.
Section 116. “The Commonwealth shall not make any law for establishing any religion, or for imposing any religious observance, or for prohibiting the free exercise of any religion, and no religious test shall be required as a qualification for any office or public trust under the Commonwealth.” This prevents the Commonwealth from passing laws that might establish an ‘official state religion’, or hinder the worship of specific religions. It is one of the Constitution’s few explicit expressions of individual rights. This section has been at the centre of several High Court actions and challenges.
Explicit restrictions on State power can be found in Sections 109, 114 and 115 of the Australian Constitution:
Section 109. “When a law of a State is inconsistent with a law of the Commonwealth, the latter shall prevail, and the former shall, to the extent of the inconsistency, be invalid.” This is somewhat controversial section says where there is conflict between Commonwealth and State law, the Commonwealth law shall prevail. In these situations the Commonwealth can legislate on areas of concurrent law and use Section 109 to override existing State laws.
Section 114 (defence forces) and Section 115 (currency) specifically instruct that “A State shall not…” legislate in those areas. The exclusive powers of the Commonwealth block the States from making laws in these areas.