President of the Senate (Australia)
The position is provided for by Section 17 of the Constitution of Australia. The Senate elects one of its members as president at the start of each new term, or whenever the position is vacant. This is usually—though not necessarily—a member of the party or coalition that holds the most seats in the Senate. The largest party in the Senate is not always the governing party, as government is determined by the House of Representatives. The President of the Senate and the Speaker of the House of Representatives may consequently be from different parties.
Parliament of Australia
The Constitution allows Parliament to determine the number of Senators by legislation, provided that the six original states are equally represented. Furthermore, the Constitution provides that each original state is entitled to at least six Senators. However, neither of these provisions applies to any newly admitted states, or to territories. Pursuant to an Act of Parliament passed in 1973, Senators are elected to represent the territories. Currently, the two Northern Territory Senators represent the residents of the Northern Territory as well as the Australian external territories of Christmas Island and the Cocos (Keeling) Islands. The two Australian Capital Territory Senators represent the Australian Capital Territory, the Jervis Bay Territory and since 1 July 2016, Norfolk Island. While only half of the State Senate seats go up for re-election each three years (except in the case of a double dissolution) as they serve six year terms, all of the Territory Senators must face the voters every three years.