This section deals with the principal Commonwealth Act relating to the environment. Following extensive negotiations with the States and Territories, the Commonwealth Parliament passed legislation in 1999 to clarify the extent of Commonwealth responsibility for the environment. This legislation, the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), implements the Intergovernmental Agreement on the Environment, which was signed by all three levels of government in 1992. The introduction of the EPBC Act represents the most significant change to Commonwealth environmental laws since the 1970s.

The EPBC Act aims to regulate amongst other issues, matters of national environmental significance (MNES). These are set out below.