Chapter III and state courts 

Chapter III of the Constitution deals with the judicature. Its constraints on the Commonwealth are strict and well defined. Its constraints on the States are indirect but increasingly significant, and they flow from a single structural fact: state courts can be invested with federal jurisdiction, so they form part of an integrated national court system.

The Commonwealth position: Boilermakers

R v Kirby; Ex parte Boilermakers' Society of Australia (1956) 94 CLR 254 established a strict double separation at the federal level:

• The judicial power of the Commonwealth may be vested only in a Chapter III court — the High Court, a federal court created by Parliament, or a state court invested with federal jurisdiction.
• A Chapter III court may not be given non-judicial power, except powers incidental to the exercise of judicial power.

The rationale is the protection of judicial independence, secured by the tenure and remuneration provisions of s 72. A body that is not a Chapter III court cannot adjudicate; a court that adjudicates cannot be turned into an arm of the executive.

The doctrine has known qualifications. Non-judicial functions may be conferred on a judge as an individual rather than as a member of the court — the persona designata exception — and courts may exercise powers that, though discretionary, are incidental to the judicial function.

Persona designata and incompatibility

The persona designata exception is itself limited. A function conferred on a judge personally is invalid if it is incompatible with the performance of judicial functions or with the integrity of the court of which the judge is a member.

Incompatibility arises where the function requires the judge to act at the direction of the executive, where it involves them so closely in executive activity that public confidence in their independence is diminished, or where the function must be performed without the ordinary incidents of judicial process. Consent of the judge does not cure incompatibility.

The States: no separation of powers requirement

State constitutions do not entrench a separation of judicial power. A state parliament may confer non-judicial functions on its courts and judicial functions on tribunals, and it may abolish or restructure its courts.

That freedom is not unlimited, and the limits come from Chapter III itself.

The Kable principle

Because s 77(iii) permits federal jurisdiction to be invested in state courts — and s 39(2) of the Judiciary Act 1903 (Cth) does invest it³ — those courts must remain fit to receive it. Kable v Director of Public Prosecutions (NSW) (1996) 189 CLR 51 held that a state legislature cannot confer on a state court a function incompatible with its institutional integrity as a repository of federal jurisdiction.¹

The legislation in Kable authorised the Supreme Court to order the continued detention of a single named person, on the balance of probabilities, where the court was satisfied he was more likely than not to commit a serious act of violence. The features that produced invalidity included that it was directed at one identified individual, that it required a prediction rather than adjudication of guilt, and that it enlisted the court to give the appearance of judicial process to what was essentially an executive decision.

Later cases have clarified that the principle is about institutional integrity, not about whether a function is "judicial". Indicia of incompatibility include:

• being directed at a named individual rather than by general law;
• requiring the court to act on the executive's opinion or at its direction;
• excluding the ordinary incidents of judicial process — reasons, open hearing, rules of evidence, an effective right to be heard; and
• requiring the court to act in a way that makes it appear to be an instrument of the executive.

The principle is applied sparingly. Preventive detention and control order regimes have frequently been upheld where the court retains genuine decisional independence and ordinary process. Kable itself has been described as a decision on unusual facts, but the principle has been repeatedly reaffirmed and extended to state tribunals exercising functions that affect the integrity of the court system.

Fardon v Attorney-General (Qld) [2004] HCA 46⁴ is the case that marks how demanding the test is. A Queensland scheme for the continuing detention of serious sex offenders was upheld: Gleeson CJ said at [19] that "[t]he Act is a general law authorising the preventive detention of a prisoner in the interests of community protection" which "authorises and empowers the Supreme Court to act in a manner which is consistent with its judicial character", and at [20] that unless there is "something inherent in the making of an order for preventive, as distinct from punitive, detention that compromises the institutional integrity of a court, then it is hard to see the foundation for the appellant's argument". McHugh J enumerated the differences from Kable at [34]: the Act was not directed at a named person, and the court was exercising judicial power. Fardon produced six judgments — Gleeson CJ, McHugh J, Gummow J, Kirby J, Hayne J, and Callinan and Heydon JJ jointly — with Kirby J dissenting, so cite the Justice or Justices rather than "the Court".

Minister for Home Affairs v Benbrika [2021] HCA 4⁵ later considered a federal scheme comparable to the Queensland Act: Div 105A of the Criminal Code (Cth), under which a State or Territory Supreme Court may order the continuing detention of a terrorist offender. That case asked whether the power was within the judicial power of the Commonwealth, not the Kable question, and by majority the Court held that no part of Div 105A was invalid on that ground. The joint reasons of Kiefel CJ, Bell, Keane and Steward JJ noted that Gummow J, with Kirby J agreeing, had been the only member of the Court in Fardon to express a concluded view on the Commonwealth's argument that the function could be conferred under Commonwealth law, and observed that his Honour had not explained why an appropriately tailored protective scheme could not fall within an exception analogous to detention for mental illness ([23], [32]). Gageler J would have held Div 105A not wholly compatible with Chapter III and Gordon J wholly invalid. Later High Court decisions have discussed Benbrika without overruling it. In YBFZ v Minister for Immigration, Citizenship and Multicultural Affairs [2024] HCA 40⁶, a case about a visa condition imposed by regulation, the joint reasons of four Justices, which do not mention Benbrika, held that protection of the community from harm at a high level of generality is not a legitimate non-punitive purpose, and Edelman J, in separate reasons, said that the Benbrika joint reasons were wrong to treat punishment and prevention as separate categories. In EGH19 v Commonwealth of Australia [2026] HCA 7⁷, Gageler CJ and Gleeson J placed Benbrika among the Commonwealth laws that conferred federal jurisdiction on a court, and Steward J, dissenting and a member of the Benbrika joint reasons, said that it appears to have been effectively diluted or re-explained. Benbrika does not alter what Fardon decided about the Queensland Act.

Kirk and the entrenched supervisory jurisdiction

Kirk v Industrial Court (NSW) (2010) 239 CLR 531 identified a defining characteristic of a state Supreme Court: its supervisory jurisdiction to confine inferior courts and tribunals within the limits of their authority by granting relief for jurisdictional error.²

Because that jurisdiction is a defining characteristic, a state parliament cannot remove it. A privative clause purporting to do so is read down or is invalid to that extent. The reason given was structural: to permit it would create "islands of power immune from supervision and restraint".

Two consequences follow. First, jurisdictional error acquires constitutional significance at state level comparable to its role under s 75(v) federally. Second, the distinction between jurisdictional and non-jurisdictional error, which had been thought to be dissolving, retains real work — only the former is beyond the reach of a privative clause.

Federal jurisdiction in state courts

The premise of the whole doctrine is s 77(iii), which allows the Commonwealth Parliament to invest state courts with federal jurisdiction. That investment is the reason state courts must remain fit to receive it.

Two practical points follow. A state court hearing a matter arising under a Commonwealth law, or between residents of different States, is exercising federal jurisdiction, and its authority comes from the Commonwealth statute rather than from state law. And a state law that would otherwise apply is picked up and applied as surrogate federal law by the Judiciary Act, subject to any inconsistent Commonwealth provision.

This is also why a state court exercising federal jurisdiction cannot be given a function the Constitution would deny a federal court in the same matter.

Applying this in a problem question

1. Identify whether the law is Commonwealth or state, because the analysis is entirely different.
2. For a Commonwealth law, apply Boilermakers both ways: is judicial power in a non-Chapter III body, or non-judicial power in a Chapter III court?
3. Consider persona designata where the function is conferred on a judge personally, and test incompatibility.
4. For a state law, do not look for a separation of powers. Apply Kable, and reason from the specific indicia rather than asserting that a function "looks executive".
5. Where a privative clause is involved, apply Kirk and classify the error as jurisdictional or not.

Self-check

• Have I identified the polity before choosing a doctrine?
• Have I avoided asserting a state separation of powers?
• Have I reasoned from concrete indicia of incompatibility?
• Have I distinguished jurisdictional from non-jurisdictional error under Kirk?
• Have I recognised that Kable is applied sparingly and most schemes survive it?