I was looking though some OH&S training notes, and this explanation of how Australian Standards are used with OH&S laws in Victoria, seems quite useful:
Australian standards outline the minimum requirements that assist any organisation to achieve it’s minimum regulatory requirements. They are vehicles for communication between producers and users, establishing a common language, which defines quality and establishes safety criteria.
There are over 6000 Standards maintained by approximately 9000 volunteer experts serving on around 1700 technical committees, supported by a full-time staff of 280. Standards give you extra information related to health and safety in the workplace that are not included or detailed in either regulations or codes of practice.”
-CGU Safety and Risk Services – 5 Day HSR Course 2012