Volunteers, Paid Workers and OHS

I have long been intrigued by this question. Do volunteer workers working on common property need OH & S complaince? What about paid workers? Calls to DOFT can give you different answers depending on whom you ask. I understand that most buildings will have an insurance policy in place which covers uninsured workers and volunteer workers. But I have also read that inspite of that (insurance) all persons should be OH&S trained to avoid heavy penalties. I am really confused! We are talking NSW Strata if that matters.