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.
