Why is the Australian Federal Government Bicameral?

Answer 1

When the federal system was originally set up it was necessary to get the approval of all of the colony's that were going to make up the federation of Australia. Needless to say the states felt that they would require some sort of representation that was related directly to the interest of each state and would over see its interest. this led to the formation of the upper house If the state was not happy about a federal lower house ruling it would be able this way to stop approval if it could gain enough support in the senate or upper house.

Answer 2

Pretty much because we adopted parts of the British and American systems which both have 2 houses of parliament/congress.

As an aside, the state of Queensland abolished its upper house.

Answer 3

Australia has a Federal Parliament, as well as a parliament in each of its six states and two territories.