Administrative law › Module guides › Judicial review of delegated legislation

The idea

Delegated legislation is subordinate law: the regulations, rules and instruments an Act authorises the executive to make. Because such an instrument is legislative in character the ADJR Act cannot reach it, so a Commonwealth instrument is challenged under s 39B of the Judiciary Act and a State instrument through Order 56. Fix that avenue before you argue validity.

The grounds run as a ladder, and you stop at the first rung that answers. Rung one is whether the instrument falls within the empowering provision, construed together with the Act's scope and objects, so a term with no objective criterion can be read down (Evans). Rung two is improper purpose: a power may be exercised only for the purpose for which it was conferred (R v Toohey), and an ulterior purpose invalidates only where the power would not have been exercised but for it (Samrein). Rung three tests reasonable proportionality against a purposive empowering provision (Vanstone), with Project Blue Sky governing how conflicting provisions are reconciled.

Some rules carry a small icon marking the structure the rule takes. The icon is a reading aid and nothing more. The facts of the cases and the words of the rules do the work.

Attack plan

1. Fix the avenue. An instrument is legislative in character and the ADJR Act cannot reach it, so a Commonwealth instrument runs under s 39B of the Judiciary Act while a State instrument runs through O 56 (see M2).
2. Climb the ladder in order. Rung one, is the instrument within the empowering provision, construed with the Act's scope and objects (Evans, the s 188(2) pattern). Rung two, is it repugnant to the Act it sits under, the simple inconsistency that answered cl 4. Rung three, only then improper purpose (Toohey ) or reasonable proportionality (Vanstone ).
3. State the consequence. The instrument is invalid, so the reason built on it falls away.
4. Add the declaration. Whenever a reason rests on the instrument, the declaration of invalidity always joins the remedy set (see M3 and Trap T2), and the writs then attack the decision built on it. **Router:** ADJR barred, go to s 39B; then rung one within power?; then rung two repugnant?; stop if a straightforward inconsistency answers; only then rung three purpose or proportionality; then declaration plus writs and exit.

Cases at a glance

Case	In a line
Evans v New South Wales	The empowering section and the clause are construed together in light of the Act's scope and objects. Clause 7 fell outside power because "annoyance" had no objective criterion, so the instrument was read down
R v Toohey; Ex parte Northern Land Council	Regulation 5 enlarged town boundaries not for planning but to defeat a native title claim. A power may be exercised only for the purpose for which it was conferred, so the instrument was invalid
Vanstone v Clark	A determination treating a conviction as "specified behaviour" fell outside the power on construction, and separately failed reasonable proportionality against a purposive empowering provision
Project Blue Sky v ABA	Conflicting provisions are reconciled by construing them to give effect to the whole Act, identifying the leading and the subordinate provision. Breach invalidates only where that is the legislative purpose
Samrein (SUPP)	The board acquired the land for office accommodation. An ulterior purpose invalidates only where the power would not have been exercised but for it, the dominant purpose test (see M8)

The rules

R130 · What is the avenue for challenging the validity of delegated legislation? arrow The ADJR Act cannot reach delegated legislation because an instrument is legislative in character and not administrative, so a Commonwealth instrument runs under section 39B of the Judiciary Act while a State instrument runs through O 56 or the Supreme Court inherent jurisdiction.

R131 · Rung one: is the instrument within the empowering provision? staircase An instrument is within power only where it falls within the empowering provision construed in light of the scope and objects of the Act, and the two constructions are interdependent. Evans.

R132 · How are conflicting provisions reconciled when construing the instrument against the Act? staircase Conflicting provisions are reconciled by construing them to give effect to the language and purpose of the whole Act, identifying the leading and the subordinate provision. Project Blue Sky.

R133 · Rung two: is the instrument repugnant to the Act it sits under? staircase An instrument is repugnant and invalid where it contradicts the Act it sits under, as where a rule renders an applicant ineligible against the Act's own eligibility scheme or exceeds a rule making limit. s 188(2)(e).

R134 · Rung three: is the instrument made for an improper purpose? compass A statutory power may be exercised only for the purpose for which it was conferred, so an instrument made to serve a purpose alien to the Act is invalid for improper purpose. Toohey.

R135 · Rung three: does the instrument fail reasonable proportionality? compass Delegated legislation made under a purposive empowering provision is invalid where it fails the test of reasonable proportionality, a stringent test met only in an extreme case. Vanstone.

R136 · What remedy set applies where a reason rests on an invalid instrument? arrow Where a reason for the decision rests on delegated legislation that is invalid, the remedy set always includes a declaration that the instrument is invalid, and the writs then attack the decision built on it.

R137 · Where more than one purpose is in play, when does the unauthorised purpose invalidate? arrow Where more than one purpose is in play, the instrument is invalid only where the power would not have been exercised but for the unauthorised purpose, the dominant purpose test. Samrein.

R138 · Does invalidity of a clause sink the whole instrument? arrow Where the offending clause can be read down or severed and the remainder stands coherently, the court reads the instrument to the extent of its validity. Evans.

Common traps

The over-complication. Running improper purpose or proportionality where simple repugnancy answers wastes the plainer point. Climb the ladder and stop at rung two when it disposes of the clause (T11).

The missing declaration. Where a reason rests on an invalid instrument, the remedy set must include a declaration of its invalidity. Most 2025 candidates who identified the validity issue still failed to seek the declaration. Whenever the instrument grounds a reason, the declaration goes in and the writs follow (T2).

The unattacked instrument. Attacking the decision while leaving the instrument its reason rests on unchallenged concedes the reason. If a clause supplies a reason, attack the clause on the ladder first, then attack the decision built on it. The two attacks are one argument, and both are needed.

The ADJR route error. Delegated legislation is legislative in character and the ADJR Act cannot reach it. Sending the challenge to the instrument through the ADJR Act is the wrong avenue. The instrument runs under s 39B of the Judiciary Act or the Supreme Courts' inherent jurisdiction; the decision under it takes the stipulated avenue.

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