The Federation of Australia was the process by which the six separate British self-governing colonies of Queensland, New South Wales, Victoria, Tasmania, South Australia, and Western Australia agreed to unite and form the Commonwealth of Australia, establishing a system of federalism in Australia. Fiji and New Zealand were originally part of this process, but they decided not to join the federation. Following federation, the six colonies that united to form the Commonwealth of Australia as states kept the systems of government (and the bicameral legislatures) that they had developed as separate colonies, but they also agreed to have a federal government that was responsible for matters concerning the whole nation. When the Constitution of Australia came into force, on 1 January 1901, the colonies collectively became states of the Commonwealth of Australia.