Australia-wide legislation: the Australasian Legal Information Institute or perhaps "Lawlex" are good. The "Scaleplus" site also has State and territorial legislation. Findlaw is an all-purpose information centre for legal advice, finding lawyers, legislation and case reports.
Updated information about the progressive harmonisation of OHS laws across all Australian states and territories is at the Commonwealth's Safe Work Australia website.
Victorian laws led the way for much of Australia's OH&S reforming legislation. This site has useful links to legislation, Codes and related material. In particular, the progress of harmonisation of OHS laws as it affects Victoria is summarised here.
New South Wales: the NSW Law and Justice Foundation (which also has links to most other main databases, plus some judgements).
West Australian-based legislation and information ( includes links to other jurisdictions)
Queensland: legislation, advisory Codes, etc
South Australian OH&S laws
Northern Territory legislation
Commonwealth OH&S Legislation and guidance material
Standards Australia - includes abstracts of most standards
International Standards Organization (ISO)
State WorkCover or equivalent Authorities:
Northern Territory Work Health Authority
Queensland Department of Industrial Relations, Workplace Health and Safety:
Tasmania Workplace Standards:
COMCARE (Commonwealth Government)
NOHSC (National Occupational Health and Safety Commission)
NIOSH (in the USA)
NIH (in the USA)