The people of Australia voted in referendums from 1898 â `` 1900 to accept the Constitution . The Constitution was then passed as a part of the Commonwealth of Australia Constitution Act 1900 ( Imp ) , an Act of the Parliament of the United Kingdom . 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 .