"Current standard: ADR79/03, equivalent to Euro 5
Future standards: Euro 6 starting in January 2017 (type approvals) and January 2018 (all sales & registrations); long term policy is to fully harmonize Australian regulations with UNECE standards.
Applicability: New vehicles including petrol (gasoline) and diesel cars, light goods vehicles, and medium goods vehicles, as well as forward control passenger vehicles and large motor tricycles." (http://transportpolicy.net/index.php?title=Australia:_Light-duty:_Emissions)
These standards apply to vehicles of weight up to 3.5 tons