Assistant MinisterのTom Rogers さんは、Motor Vehicle Standards Act 1989のSection 7 に基づき車両基準を定めます。そのSectrion 7 には以下のように書かれています。The Minister may, by legislative instrument, determine vehicle standards for road vehicles or vehicle components.
https://www.legislation.gov.au/Details/C2016C00857(なお legislative instrumentの説明は以下の通りです。"... Parliament, however, frequently enacts legislation containing provisions which empower the executive government, or specified bodies or office-holders, or the judiciary, to make regulations or other forms of instruments which, provided that they are properly made, have the effect of law. This form of law is referred to as “delegated legislation”, “subordinate legislation” or “legislative instruments”
https://www.aph.gov.au/binaries/senate/pubs/odgers/pdf/chap1... )