Re Construction Forestry and Mining Employees Union Ex Parte Multiplex Constructions Pty Ltd

The applicant, Multiplex Constructions Pty Ltd, sought a writ of prohibition against the respondent, the Construction Forestry and Mining Employees Union (CFMEU), to prevent the CFMEU from continuing proceedings in the Industrial Relations Commission of New South Wales. The dispute concerned allegations that the CFMEU had engaged in conduct in contravention of s 298M of the *Industrial Relations Act 1940* (NSW), which prohibited secondary boycotts. The matter came before the High Court of Australia.

The primary legal issue before the High Court was whether the CFMEU's conduct, in directing its members not to work on a construction site due to concerns about the safety of a particular subcontractor's work, constituted a secondary boycott within the meaning of s 298M of the *Industrial Relations Act 1940* (NSW). This involved determining whether the actions of the CFMEU were directed at achieving a purpose prohibited by the section, specifically the obstruction of a third party (the subcontractor) in their business dealings with the principal contractor (Multiplex).

Mason C.J. considered the purpose and effect of the CFMEU's actions. His Honour found that the union's direction to its members not to work was intended to pressure Multiplex to cease engaging the subcontractor. This pressure was aimed at causing Multiplex to terminate its contract with the subcontractor, thereby directly affecting the subcontractor's business. Consequently, the conduct was held to be a secondary boycott as defined by the Act, as it involved the obstruction of a third party in their business relations with another person. The court applied the principles of statutory interpretation to ascertain the legislative intent behind the prohibition of secondary boycotts, focusing on the impact of the union's actions on third-party commercial relationships.

The High Court made absolute the order nisi for a writ of prohibition, restraining the CFMEU from further proceeding with its application in the Industrial Relations Commission of New South Wales.