chalkline. Snap the line. Build to it.
regulation Health and safety (WHS) 8 min read

WHS duties when engaging subcontractors

PCBU duties when engaging subcontractors: consultation, SWMS collection, site induction, and principal contractor obligations for Australian builders.

By Dan Waring. Last updated 8 May 2026. Verified 8 May 2026.

Ask Chalkline about this →

In plain English

When a subcontractor is engaged on a residential job, both the engaging party and the subcontractor are separately responsible as PCBUs. The law requires each to consult, cooperate and coordinate on any matter where duties overlap, including fall risks, HRCW, and site rules.

The principal contractor threshold in most jurisdictions is $250,000 in construction work value. Once you cross it, you take on a formal set of duties on top of your baseline PCBU obligations: a written WHS management plan before work starts, collection of every subcontractor’s SWMS before HRCW begins, a site-specific induction for every person before they touch the job, and visible site signage.

Below $250,000 you still have all your PCBU duties, you just do not formally become the “principal contractor” in the regulatory sense.

What it requires

1. Baseline PCBU duty (all jobs, all values)

Under Work Health and Safety Act 2011 (model law) s 19, every PCBU must, so far as is reasonably practicable, ensure the health and safety of their own workers and not expose other persons to risk from the work.

“Worker” under s 7 includes employees, contractors, subcontractors, employees of subcontractors, and labour-hire workers assigned to the undertaking (verified 2026-05-08).

Engaging a subcontractor does not transfer your duty. A PCBU cannot eliminate its WHS obligations by sub-contracting work (Safe Work Australia, Fact Sheet - WHS Duties in a Contractual Chain, verified 2026-05-08).

2. Consultation, cooperation and coordination between PCBUs

Under WHS Act ss 46-49, when two or more PCBUs share a duty in relation to the same matter, each must, so far as is reasonably practicable, consult, cooperate and coordinate activities with every other duty holder (verified 2026-05-08).

On a residential construction site this is the normal state of affairs: you (the builder/principal contractor) and every subcontractor are separate PCBUs, and your activities regularly create overlapping hazards.

What the three duties mean in practice:

DutyWhat it requires
ConsultShare relevant WHS information with the subcontractor before work starts and whenever conditions change. Get their input on hazards and control measures.
CooperateAct on the information shared. Implement controls agreed between you. Don’t undermine another PCBU’s controls.
CoordinatePlan the work sequence and site access so that one trade’s activities do not create uncontrolled hazards for another. For example, co-ordinate roof work and ground-level traffic so the exclusion zone under roofers is maintained when concretors are delivering.

Consultation is required (s 49) when identifying hazards, deciding on risk controls, or carrying out work that may affect others. The Safe Work Australia Model Code of Practice: WHS Consultation, Cooperation and Coordination (February 2022) is adopted in NSW, Qld, and most model-law jurisdictions (verified 2026-05-08). A toolbox talk before a new subcontractor mobilises, documented with date and attendees, satisfies most consultation obligations.

3. Principal contractor duties (construction projects $250,000 and over)

Under Work Health and Safety Regulation 2017 (NSW) reg 293, a person who commissions a construction project is the principal contractor for that project. The same threshold applies in all model-law jurisdictions under the equivalent regulation number (verified 2026-05-08).

A construction project is defined as construction work where the cost exceeds $250,000.

You can appoint another PCBU as principal contractor and authorise them to manage and control the workplace. That appointment must be explicit and in writing; verbal arrangements do not transfer the formal duties.

Principal contractor must:

  • Prepare a written WHS management plan before work starts (responsibility structure, coordination arrangements, emergency procedures, site rules, SWMS review system)
  • Inform all subcontractors and workers of plan content before they start (reg 295, NSW); keep accessible until completion or 2 years post-notifiable incident
  • Collect each subcontractor’s SWMS before HRCW begins (regs 299-301); review; require revision if inadequate
  • Post site signage: principal contractor name and 24-hour contact number
  • Run site-specific induction for every person before they start

4. SWMS obligations on the subcontractor

The duty to prepare a SWMS sits with the PCBU carrying out the HRCW, which is usually the subcontractor. The subcontractor must:

  • Prepare the SWMS before starting any HRCW (see SWMS: When it’s required and how to write one for the 18 trigger categories)
  • Prepare it to reflect the actual site conditions (access, proximity to other structures, other trades working at the same time)
  • Give a copy to the principal contractor before work commences (WHS Regulation reg 301)
  • Review and revise the SWMS if conditions change

As principal contractor, you must not allow HRCW to begin if no SWMS has been provided or if the SWMS is obviously inadequate (Safe Work Australia, Code of Practice: Construction Work 2022, verified 2026-05-08).

5. Site induction (all projects)

Every person needs a general construction induction (white card, CPCWHS1001) before working on any Australian construction site (recognised nationally; lapses after 2 years out of industry) (SafeWork NSW, verified 2026-05-08). As principal contractor you must also run a site-specific induction covering site rules, hazards, emergency procedures and SWMS before anyone starts work. Generic online inductions do not substitute. Keep records (names, dates, who ran it) throughout the project.

6. Dual status of subcontractors

Subcontractors are simultaneously a PCBU (with duties to their own workers and their own SWMS obligations) and a worker in your undertaking (required under WHS Act s 28 to follow reasonable safety instructions and not create risks for others). A subcontractor cannot refuse to comply with site rules by pointing to their own PCBU status: both roles attach at once.

What it doesn’t cover

Practical implications

For the engaging party (sub-$250k): Confirm white card, check insurance (Certificate of Currency), brief on site hazards, obtain SWMS for any HRCW, agree in writing on who controls shared risks.

For the engaging party ($250k+, principal contractor): Prepare WHS management plan before work starts (MBA/SafeWork NSW publish templates), run site-specific inductions, share the plan with all on site, collect and review SWMS before HRCW begins, post the required site sign. Review SWMS when conditions change; keep induction records.

For subcontractors (all projects): Have your white card on hand. Supply SWMS to the principal contractor before any HRCW. Complete the site induction before starting. Comply with site rules. As a PCBU you also owe these duties to your own workers.

For the pre-engagement checklist (licence, insurance, ABN, SWMS commitment), see Engaging a subcontractor: the basics.

Penalties

WHS Act penalties are indexed annually. As at 1 July 2025, model WHS Act maximum penalties are (Safe Work Australia, verified 2026-05-08):

CategoryBody corporateIndividual PCBU/officer
Category 1 (reckless)~$11.84M~$2.37M + imprisonment
Category 2 (risk of death/serious injury)~$2.37M~$475K
Category 3 (general failure)~$790K~$158K

No SWMS before HRCW = Category 3 minimum. Serious injury results = Category 2 or 1. In NSW 2025-26, 1 penalty unit = $123.31 (verified 2026-05-08).

References

See also

Last updated: 2026-05-08. Verified: 2026-05-08. Quarterly review for currency.

Related articles