PCBUs should carefully assess their duty - under the model WHS Act - to consult with HSRs who represent cross-PCBU work groups, lawyers have advised.

"It is important for all PCBUs to understand what impact harmonisation has on their interactions with [health and safety representatives], particularly where multiple PCBUs are involved," Henry Davis York Lawyers partner Scarlet Reid, and lawyer Tom Reaburn, say in a report.

Under sections 50 to 74 of the model Act, an HSR represents a "work group", and has the power to investigate workers' safety complaints, direct workers to cease unsafe work, and issue provisional improvement notices (PINs).

What constitutes a work group is determined in negotiations between PCBUs and workers, Reid and Reaburn say.

"Relevantly, where there are multiple PCBUs [at a workplace], a work group may be formed across two or more PCBUs," they say.

"It follows that an HSR may represent a range of employees, contractors and subcontractors each from different companies.

"[This] means that an employer can receive a PIN, not only from one of their own employees, but from an employee of a contractor, client or customer."

According to Reid and Reaburn, PCBUs that are faced with complex working arrangements "need to be aware of the risks associated with cross-company workgroups and HSRs and consider the impact of safety consultation arrangements on their commercial relationships with other PCBUs".

PCBUs should assess their duty to consult, cooperate and coordinate with other PCBUs on safety matters before work commences, and "clearly outline how each PCBU will meet its duty in any relevant contractual negotiations or documentation", they say.