If you want to find out more about the law and the level of access buildings should provide you can download a Guideline on the application of the Premises Standards at https://www.humanrights.gov.au/guidelines-application-premises-standards

If you want to find out more about the technical requirements for the design and construction of features such as ramps, stairs or accessible unisex toilets you can purchase a copy of the technical standard (AS 1428.1) from http://infostore.saiglobal.com/store/default.aspx