Residential stratas are specifically exempted from WHS Acts around Australia unless they directly employ someone (that means payroll tax, superannuation etc). Most stratas use contractors and so have the same WHS exemption status as private house owners.
What it means is that when work is done on site by contractors it’s the contractor (or their employer, if there is one) that must ensure that by all WHS requirements are met. That might mean that certain qualifications are required and that certain equipment needs to be used etc.