Even if the United Kingdom Parliament were to remove the Commonwealth of Australia Constitution Act 1900 , it would have no effect on Australia . The most important is the Constitution of the Commonwealth of Australia . The Constitution was approved in referendums held over 1898 â `` 1900 by the people of the Australian colonies , and the approved draft was enacted as a section of the Commonwealth of Australia Constitution Act 1900 ( Imp ) , an Act of the Parliament of the United Kingdom .