Parliament and the courts

This fact sheet outlines the relationship between the Australian Parliament and federal courts, including the separation of powers, sources of law and key High Court of Australia cases that have impacted on the powers of the Australian Parliament.

Separation of powers

The Australian Constitution outlines how the power to make and manage Australian law is divided between the Australian Parliament, the Executive – the Australian Government – and the Judiciary. This division is based on the principle of the 'separation of powers'.

Under this principle:

  • the Australian Parliament has the power to make laws for all Australians.
  • the High Court of Australia and other federal courts have the power to interpret laws made by Parliament and judge if laws are consistent – valid – with the Constitution.

The Parliament and the Judiciary are independent of each other. This allows each to keep a check on the actions of the other. However, the Parliament, Executive and Judiciary are not completely separate; for example, the Parliament can create Federal courts and the Executive appoints High Court judges.

The Australian Parliament has the right to make, amend or repeal any law within the limits of the Constitution. The Judiciary cannot challenge or review this right of the Australian Parliament. Parliament’s law-making power takes precedence over that of the Judiciary; statute laws made by Parliament override judge-made law—common law. This is called parliamentary supremacy.

Sources of law



Legislation (statute law)

Judge-made law (common law)

Delegated legislation (statute law)

Constitutional interpretation in judgements

Abrogation—Parliament overrides a court made law (common law)

Statutory interpretation—giving meaning to words in statute laws and providing precedent to the way it will apply in certain cases

Significant High Court of Australia cases which have impacted the powers of the Australian Parliament

The High Court of Australia interprets the Australian Constitution and settles disputes about its meaning. High Court judgements can have far reaching consequences. They can check Parliament’s powers or expand it, or confirm the power of the Parliament to make laws in specific areas.






Victoria v Commonwealth (1926) (Roads Case)

Victoria challenged the ability of the Commonwealth to dictate how states spend money (for example, to build major roads) granted to them using section 96 of the Constitution.

Can the Commonwealth grant money to the states using section 96 on the condition it is spent in an area of state responsibility?

The High Court found the Commonwealth could tell the states how to spend money granted to them, even if it was in an area of state responsibility, such as roads.

This case changed the balance of power between the Commonwealth and the states by allowing the Commonwealth to have a greater say in areas of state responsibility, such as education and health.

Mabo and others v Queensland (No 2) (1992)

In 1982 Eddie Koiki Mabo and 4 others started their legal claim for ownership of the island of Mer in the Torres Strait. The Queensland Government had earlier tried to extinguish the Meriam people’s property rights but the High Court had found this had been unlawful in Mabo v Queensland (No 1).

Did Aboriginal and Torres Strait Islander peoples own their land before the British claimed ownership?


Had Aboriginal and Torres Strait Islander peoples rights to their land been completely abolished when Britain claimed ownership of Australia?

Six of the 7 High Court judges rejected the doctrine of terra nullius, which stated Australia did not belong to any one before Britain claimed ownership. The decision recognised in Australian law that Aboriginal and Torres Strait Islander peoples rights and interests to their land come from their traditional laws and customs. These rights and interests were not abolished when Britain claimed ownership.

In response to this judgement, the Australian Parliament passed the Native Title Act (1993) which attempted to codify the High Court decision and set out a framework for Aboriginal and Torres Strait Islander peoples to seek recognition of their native title rights.

Love v Commonwealth; Thoms v Commonwealth (2020)

Immigration law in Australia allows for non-citizens to be deported after being sentenced to imprisonment for 12 months or more. Two Aboriginal men—both born outside of Australia and non-citizens—were to be deported after serving their sentences.

Can an Aboriginal Australian be considered an ‘alien’ in Australia, according to section 51 (xix) (‘aliens’ power) of the Constitution?

The majority of High Court judges—each issuing a separate judgement—found that Aboriginal Australians were not subject to the ‘aliens’ power.

The full impact of this judgement is yet to be tested. However, both Mr Love and Mr Thoms were released from immigration detention and not deported. The judgement limited the Australian Parliament’s powers to make laws using the ‘aliens’ powers and confirmed Aboriginal and Torres Strait Islander people could not be considered ‘alien’ from Australia.


Court hierarchy.

A graphic showing the hierarchy of courts in Australia.

Parliamentary Education Office


This diagram shows the hierarchy of courts in Australia. At the top is the High Court of Australia. Underneath this court are:

  • State/territory courts
    • Supreme court
    • Intermediate courts (county/district courts)
    • Lower courts (local/magistrates court)
  • Federal courts
    • Federal court/family court
  • Federal magistrates court

Separation of powers in Australia.

This diagram illustrates the principle of the separation of powers. The Parliament, Executive and Judiciary have separate powers.

Parliamentary Education Office (


This diagram illustrates the separation of powers in the Australian system of government. The Parliament (represented by an icon of Australian Parliament House) has the power to make and change law. The Executive (represented by a group of people) has the power to put law into action. The Judiciary (represented by an icon of a scale) has the power to make judgements on law. The three groups—Parliament, Executive and Judiciary—are connected.