Commonwealth electoral boundaries are periodically reviewed to deal with population changes between and within states and territories.

The two main grounds for redistributions are -

• Changes in a state or territory's entitlement to representation in the House of Representatives
• Passage of time, with each state and territory being reviewed seven years after the last redistribution.

The next federal election will be fought on new boundaries in four states and the two territories.

The seven year rule triggered redistributions in Queensland (30 seats), Tasmania (5 seats) and the Northern Territory (two seats). There was no change in seat numbers with these redistributions, the new boundaries merely bringing the electoral enrolment in each division back within the permitted variation from state average.

Redistributions in Victoria, South Australia and the ACT were undertaken due to changes in representation entitlement. Victoria increased by one seat from 37 to 38, the ACT up one from two seats to three, while South Australia lost a seat, down from 11 seats to 10.

Overall the House of Representatives has increased from 150 to 151 seats.

Where the Coalition won 76 seats in the 150 member House of Representatives in 2016, they notionally hold only 74 seats in the new 151 member House, reduced to 73 seats having lost the Wentworth by-election. Labor's numbers increase from 69 to 72.

The redistribution in Victoria has turned the Victorian seats of Corangamite and Dunkley from Liberal seats into notional Labor seats. Labor notionally holds the new seats of Bean (ACT) and Fraser (VIC), but loses a seat with the abolition of Port Adelaide (SA).

A new electoralpendulum is set out at the bottom of this page.

Summary of Seats Held by Party

Click on the state name below for more details of the boundary changes in each state.

Northern Territory

Electoral boundaries in the Northern Territory have been unchanged since the Territory was first divided into two seats ahead of the 2001 election. The 2009 redistribution left the boundaries undisturbed, but the 2017 redistribution has produced an adjustment to the boundary between Solomon and Lingiari to deal with the faster enrolment growth rate of Darwin compared to the rest of the Northern Territory.

Tasmania

A redistribution of electorates in Tasmania has been undertaken under the seven year rule. As an original state, Tasmania is guaranteed five seats in the House of Representatives. As well as bringing enrolments in electorates back towards equality, the redistribution has changed the name of the electorate of Denison to Clark.

Queensland

A redistribution under the seven year rule has been undertaken for Queensland's 30 seats. Only minor boundary changes were required to bring seats back within the permitted variation from quota.

Victoria

Victoria's population has been growing at a faster rate than the rest of the nation, resulting in the state gaining a seat. The redistribution is being undertaken to increase the number of divisions from 37 to 38. A new seat called Fraser has been created in western Melbourne and name changes have been made to five other divisions.

Australian Capital Territory

The ACT has been undergoing population growth faster than the rest of the nation, resulting in its representation increasing from two to three members.

South Australia

The relative decline in South Australia's population has seen the state lose a seat, reduced from 11 to 10 seats. The Labor seat of Port Adelaide has been abolished, increasing the Labor margin in neighbouring Labor seats. The electorate of Wakefield has also been re-named Spence.

New Electoral Pendulum

Set out below is a new electoral pendulum for the 151 seat House of Representatives created by the redistributions. Seat holdings correspond to the table at the top of this page.

(*) - Corangamite and Dunkley are currently Liberal-held seats but become notionally Labor-held on the new boundaries.

(+) - Wentworth was gained from the Liberal Party by Independent Kerryn Phelps at a by-election. The by-electuion margin has been used in the pendulum.

Other by-elections and resignations from parties since 2016 have been ignored.

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