Redistributions are held to keep the number of enrolled voters in each seat roughly equal. In Australia, this equal population per seat is possible for a particular state or territory’s seats, but not for all seats in the House of Representatives.
ABC election analyst Antony Green said in June 2023 that all original states are entitled to at least five House seats, so Tasmania has five seats even though its population should only give it three.
Redistributions are needed when the population of a state increases or decreases relative to the overall Australian population, such that the state is entitled to either add a seat, or a seat is removed from that state.
