The Workplace Relations Act 1996 (Cth) was intended to operate to the exclusion of present and future State and Territory industrial regimes in relation to constitutional corporations and their employees (as defined in ss 5(1) and 6(1)), subject to exceptions.

The Melbourne Corporation principle applies where the curtailment or interference with exercise of a State's constitutional power is significant, judged qualitatively and by reference to practical effects; where a State or its agency voluntarily enters into an enterprise agreement, the statutory regime for making and approving such agreements does not impose a significant impairment, interference, curtailment, control or restriction that attracts the implied limitation.

The implied limitation on Commonwealth power to regulate matters affecting State governmental capacity is not applicable to provisions operating by reference to a State or its agencies having voluntarily entered into an agreement subsequently given statutory force, but only on condition that the parties made the agreement which was approved by the FWA.

An enterprise agreement is not involuntary for purposes of the Melbourne Corporation principle merely because it may have been entered into in response to threat or actuality of protected industrial action, unless the State entity has been forced to propose the agreement due to its inability factually to endure the protected industrial action.

The fact that a measure concerns a core governmental function does not automatically trigger Melbourne Corporation immunity; the immunity protects the State's capacity to determine terms and conditions of engagement at higher levels of government.

A law denying access to discretionary powers where an alternative system of compulsory arbitration is unavailable is not discriminatory against a State merely because that State has abolished its own compulsory arbitration system.

The ordinary canon of construction is that a statute does not bind the Crown unless it is mentioned expressly or by necessary implication. However, the Commonwealth Parliament may exercise its legislative powers to affect a State or authority formed by a State.

The purpose of s37C(3) is to prevent a private sector award from being extended to bind employees and employers already covered by a public sector award; the provision is only enlivened if the relevant public sector awards extend to and bind the particular employees which the Award would otherwise extend to and bind.

The principles for determining inconsistency between Commonwealth and State laws under section 109 of the Constitution are well settled: federal law prevails over inconsistent State laws regardless of subject matter; the scope and meaning of the federal law must first be determined; and inconsistency may emerge as direct collision, marginal supplementary questions, or textual opposition.

Section 16(1) of the WRA marks out the field of legislative activity in relation to an employee or employer where the employer is a constitutional corporation, and the Commission's jurisdiction under the Act to deal with such matters falls within the field occupied by the WRA and is therefore excluded by the operation of s109 of the Constitution.

Although section 16(1) of the WRA does not expressly regulate common law contractual claims, the WRA covers the entire field of the relationship between constitutional corporations and their employees, and by operation of s109 of the Constitution, State laws in that field are invalid to the extent of inconsistency, even where the Commonwealth has made no detailed provision on a particular matter within that field.

A State or Territory law 'applies to employment generally' if it applies to all employers and employees in the State or Territory, or all employers and employees except those identified by reference to a class or otherwise; exceptions are exceptions from the 'all employers and employees' standard, not the reverse.