Alternative methods of determining the number of House of Representatives seats for Australia’s territories

Background: Population size determines the number of seats each Australian state and territory is entitled to in the House of Representatives. The Northern Territory (NT) and Australian Capital Territory (ACT) were allocated two and three seats, respectively, in the August 2017 determination, but by very small margins. Both territories risk losing a seat at the next determination. This would result in them having considerably more people per member of parliament than any of the states.

Aims: This paper (1) provides modelling to support the consideration of alternative rules for determining membership entitlement to the House of Representatives which does not disadvantage the NT and ACT and (2) presents population projections for future determinations under the current and alternative rules.

Data and methods: Population projections for the states and territories were produced for three demographic scenarios. The resulting numbers of seats for the NT and ACT were calculated for each scenario under the current and proposed alternative seat entitlement rules.

Results: Under the existing rules the NT and ACT would only keep their current number of seats at the next determination if they experienced higher net in-migration than in recent years. Under the alternative seat entitlement rules suggested, the NT and ACT would be very unlikely to lose any seats and would almost certainly gain seats in ensuing decades.

Conclusions: There is a case for re-examining the way the states and territories are allocated seats in the House of Representatives.