BUSN7052 Chap.1 The Australian Legal System and the Constitution
The Australian Legal System and the Constitution
Australian business law sits on a constitutional frame. This chapter explains the three tiers of government, the separation of legislative, executive and judicial power, and the modified Westminster model in which ministers sit in Parliament.
It then works through the constitutional sections commercial problems use: the section 51 heads of power, the section 92 guarantee of free interstate trade, section 109 inconsistency, section 122 power over territories such as the ACT, and section 128 referendums, before tracing how English law was received and how Australia became legally independent.
What this chapter covers
- 01
Three tiers of government and their law-making roles
- 02
Separation of powers and responsible government
- 03
Section 51 heads of power, concurrent and exclusive
- 04
Section 92 discrimination test from Cole v Whitfield to Palmer
- 05
Section 109 for States and section 122 for territories
- 06
Reception, the Australia Acts 1986 and Mabo
Worked example · free
Does a minister sitting in Parliament breach the separation of powers?
- +1Name the three arms: the legislature makes laws, the executive implements them and the judiciary interprets and applies them.
- +2Australia uses a modified Westminster model: under responsible government ministers must be elected members of Parliament, so the legislature and executive overlap by design.
- +1The arm that must stand apart is the judiciary, in which s 71 vests Commonwealth judicial power.
- +1The minister's dual role is the intended overlap, not a breach.
Key terms
- Separation of powers
- The division of governmental power among the legislature, the executive and the judiciary.
- Head of power
- A subject on which the Constitution authorises the Commonwealth Parliament to make laws.
- Double majority
- The referendum requirement of a majority nationally plus majorities in most States.
- Terra nullius
- The false claim that Australian land belonged to no one, rejected by the High Court in Mabo.
- Responsible government
- The convention that ministers are members of Parliament and answerable to it.
The Australian Legal System and the Constitution FAQ
Why does a business law course start with the Constitution?
Many commercial statutes rest on Commonwealth heads of power: the slides tie the Corporations Act to s 51(xx) and list insurance under s 51(xiv). Knowing which level of government can legislate, and which law wins when two conflict, tells you which statute governs a dispute before you start applying its provisions.
Is section 92 a guarantee that States can never burden trade?
No. The High Court reads it as a ban on discrimination against interstate trade. A neutral rule applying to local and interstate goods alike can stand, as the crayfish size limit did, while a discriminatory measure fails unless it serves a legitimate non-discriminatory purpose without going further than necessary.
How often has the Constitution been changed?
The Week 1 slides record that only 8 of 45 referendums have succeeded. Change needs an Act of Parliament followed by a vote that wins a national majority and majorities in most States. The October 2023 Voice referendum was defeated under that test.
What did the Australia Acts 1986 change for courts?
They ended appeals from Australian courts to the Privy Council in London, so the High Court became the final court of appeal. They also removed the British Parliament's power to legislate for Australia and confirmed that the Constitution changes only through an Australian referendum.
Exam move
Draw the constitutional map once from memory: three tiers, three arms, then the sections that move power between levels. Next to each section write the question it answers in a problem, so that s 51 prompts you to look for a head of power, s 109 to look for a conflict with a State law, s 122 to look for a territory, and s 92 to look for a burden on interstate trade.
Practise the s 92 sequence of burden, discrimination and justification on two or three invented border measures, varying whether the measure falls on local traders too.
Keep a one-line note of each leading case with the single proposition it supplies: Cole v Whitfield for non-discriminatory burdens, Palmer for justification, Tasmanian Dams for the external affairs and corporations powers, and Mabo for the rejection of terra nullius.
Finally, rehearse the history as a chain of four dates with one consequence each, because short-answer questions in tutorials asked students to explain significance rather than recite facts. When you revise later chapters, notice which statutes rely on federal power, such as the Corporations Act and the Insurance Contracts Act, and which are ACT laws, such as the Civil Law (Wrongs) Act and the Sale of Goods Act.
That habit stops you from citing the wrong jurisdiction in a Canberra scenario.
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