Principal Contractor Obligations Under the WHS Regulation 2025

Under the WHS Regulation 2025, a construction project with a value of $250,000 or more triggers the appointment of a principal contractor. The person who commissions the construction work must appoint a principal contractor in writing before work commences. If no appointment is made, the person commissioning the work is deemed to be the principal contractor and inherits all associated duties. This threshold applies to the total project value including labour and materials, not just the contract sum for a single trade package. Multiple smaller packages on the same site that collectively exceed $250,000 still trigger the obligation. The principal contractor assumes control of the workplace and bears responsibility for the overall coordination of WHS across all persons carrying out work on the site. This is not a delegable duty and it cannot be contracted away through indemnity clauses or subcontract terms. Understanding when these duties are triggered is the first step in managing them effectively.

Section 309 of the WHS Regulation 2025 requires the principal contractor to prepare a written WHS management plan before work commences on site. The plan must include the names, positions, and health and safety responsibilities of all persons at the workplace whose roles involve specific WHS duties. It must set out the arrangements for consultation, cooperation, and coordination between all duty holders on the project. The plan must describe the arrangements for managing specific WHS incidents including emergency procedures, first aid provisions, and the process for notifying the regulator of notifiable incidents. It must address how SWMS will be collected, reviewed, and monitored throughout the project lifecycle. The plan must also cover site-specific induction requirements, the process for managing visitors and deliveries, and arrangements for the security of the workplace. A WHS management plan is a living document that must be reviewed and revised whenever circumstances on the project materially change, including changes to contractors, work methods, or site conditions.

The principal contractor must ensure that a SWMS is prepared for each item of high-risk construction work before that work commences. While subcontractors prepare their own SWMS as the PCBU directing that work, the principal contractor has a duty to collect these documents and ensure they are adequate. A cursory filing exercise does not satisfy this obligation. The principal contractor must review each SWMS to confirm it identifies the high-risk construction work, lists the hazards and risks associated with that work, describes the control measures to be implemented, and explains how those controls will be monitored. Where a SWMS is inadequate, the principal contractor must require the subcontractor to revise it before authorising the work to proceed. The principal contractor must also have arrangements in place to monitor compliance with the SWMS on site. Workers must have ready access to the SWMS relevant to their tasks. The principal contractor should maintain a register of all SWMS on the project, their revision status, and the date each was last reviewed for adequacy.

The principal contractor is responsible for erecting and maintaining signage that identifies the principal contractor by name and telephone number, marks the boundary of the workplace, and directs persons to the site office or sign-in point. Emergency procedures must be coordinated across all contractors on the project. This includes establishing evacuation routes, assembly points, emergency communication systems, and the roles and responsibilities of wardens and first aiders. The principal contractor must ensure that emergency drills are conducted at intervals appropriate to the risk profile of the project. Site-specific induction is another core obligation. Every person entering the workplace must receive an induction that covers the site layout, emergency procedures, high-risk activities in progress, traffic management arrangements, and the location of first aid and emergency equipment. The principal contractor must keep records of all inductions delivered and ensure that induction content is updated when site conditions change. Visitor management procedures must prevent unauthorised access to areas where high-risk construction work is being performed.

Section 27 of the WHS Act imposes a positive due diligence duty on officers of a PCBU, including directors and senior managers of a principal contractor. An officer must take reasonable steps to acquire and maintain knowledge of WHS matters, understand the nature of the operations and the hazards and risks associated with them, ensure the PCBU has appropriate resources and processes to eliminate or minimise those risks, and ensure the PCBU has processes for receiving and responding to WHS information. The November 2024 decision in Diona Pty Ltd v SafeWork NSW reinforced the personal exposure of officers in construction. The court confirmed that an officer cannot rely on delegation alone and must demonstrate active engagement with the WHS management systems of the business. Officers who fail to exercise due diligence face personal penalties of up to $345,000 for a Category 2 offence. This liability cannot be insured against in most Australian jurisdictions. Principal contractor obligations therefore require board-level visibility and governance, not just site-level management.