ABS Population Statistics confirm WA to gain a new House seat, Victoria and NSW to lose seats

The Australian Bureau of Statistics (ABS) has released state population figures this morning that confirm a change in seat numbers for three states at the next Federal election.

New South Wales representation will be reduced from 47 to 46 seats, Victoria reduced from 39 to 38 seats, while Western Australia will gain a seat, increasing from 15 to 16 seats.

Other jurisdictions remain unchanged, Queensland with 30 seats, South Australia 10, Tasmania five, Australian Capital Territory three and Northern Territory two.

The next election will be for a 150 member House of Representatives, down one from the current 151 seats.

The current elected members per state remain unchanged until the next election, due between August 2024 and May 2025. Redistributions will take place in the three affected states to bring the number of electoral divisions in line with the change in allocated members.

The change in numbers will become official in the last week of July, one year after the first sitting of the current House of Representatives, when the Australian Electoral Commissioner Tom Rogers issues a formal determination of House representation by state and territory.

Commissioner Rogers has no personal choice in making the determination as the method is strictly defined in law. For states the Commissioner will apply the formula set out in Section 24 of the Constitution. For the Territories the Commissioner will use the formula set out in the Electoral Act. The Constitution also states that the Commissioner will use the “latest statistics of the Commonwealth”, a phrase the High Court and Parliament has determined will be the quarterly population statistics, that is today’s ABS release.

The precise calculations around how seats are allocated is explained inside this post.

Once the new numbers are officially announced at the end of July, redistributions to implement the changed seat numbers will get underway in NSW, Victoria and Western Australia. Based on past redistribution timelines, the process of drawing new boundaries should be completed by early July 2024, in time for use at the next election.

The changes in Victoria and Western Australia reverse changed numbers that first applied at the 2022 election.

For NSW, the reduction to 46 continues a long term trend. When the parliament was increased in size in 1984, 51 of the 148 seats were in NSW. The state lost seats at the 1993, 2007, 2010 and 2016 elections.

The latest changes have come about because of changes in relative state populations. The populations of NSW and Victoria have been growing more slowly than other state, meaning both states declined relative to other states. In large part this has come about because of the two year halt to immigration, ending the usual large migrant inflow to the nation’s two largest states. Despite closing its state border in the same period, over three full years Western Australia has been a beneficiary of internal migration from other states.

How the Determination is made

Under Section 24 of the Constitution, the following calculations are undertaken to allocate members and seats to states.

First the Commissioner uses the ABS statistics to determine the population of the Commonwealth. An important point here is the the High Court has ruled that the population of the Commonwealth is the population of the states, that is excluding the Territories.

The Constitution then specifies that a quota be calculated by dividing the population of the Commonwealth by twice the number of Senators. The High Court has also ruled on this provision and the divisor is twice the number of State Senators. The four Territory Senators are ignored, the number of State Senators is 72 so the divisor is 144.

Based on today’s ABS report, the quota is 25,552,408 divided by 144 which equals 177,447.277780

The population of each state and territory is then divided by the quota, the resultant quotient determining the number of members each jurisdiction will be allocated.

The Constitution sets out the following rules for allocating seats to states

  • A number of seats equal to the whole number part of the quotient is allocated to each state.
  • If the fractional part of the quotient is greater than 0.5, the state is allocated an extra seat.
  • Notwithstanding the above calculations, all original states are entitled to five seats. That’s why Tasmania retains five House seats.

Allocation of seats to Territories is determined by the Electoral Act rather than the Constitution. Before the 2022 election, the Commonwealth Parliament altered the formula for territories so the following rules apply to the quotient of each territory

  • A number of seats equal to the whole number part of the quotient is allocated to each territory.
  • If the quotient is greater than two and less than three, then if the fractional part of the quotient is greater than 0.4, then the territory is allocated an extra seat. (This rules currently applies to the ACT.)
  • If the quotient is greater than one and less than two, then if the fractional part of the quotient is greater than 0.333333, then the territory is allocated an extra seat. (This rules currently applies to the NT.)

The Calculation Table

All the calculations that apply to the current determination are set out below. (Try turning your screen 90 degrees if you are on a mobile)

Electorate Population Quotient Whole
New South Wales 8,238,801 46.42957110 46 .. 46 -1
Victoria 6,704,281 37.78181939 37 1 38 -1
Queensland 5,378,277 30.30915474 30 .. 30 ..
Western Australia 2,825,178 15.92122480 15 1 16 1
South Australia 1,834,275 10.33701403 10 .. 10 ..
Tasmania 571,596 3.22121594 .. .. 5 ..
Australian Capital Territory 460,855 2.59713762 2 1 3 ..
Northern Territory 250,149 1.40970886 1 1 2 ..

Source: ABS national, state and territory population statistics.
Note: Around 5,000 voters in other territories are not included in above table. Norfolk island and Jervis Bay will be added to the ACT. Christmas and Cocos Keeling Islands are added to the Northern Territory.

The above changes will result in the current 151 member House of Representatives being reduced to 150 at the next election.

All current members and seats remain in place until writs are issued for the next election. Over the next year, the three states with changed representation will undergo redistributions to draw boundaries for a number of electorate equal to the new number of members to be elected.

The chart below shows the seats per state and territory at elections since the House and Senate were increased in size at the 1984 election.

10 thoughts on “ABS Population Statistics confirm WA to gain a new House seat, Victoria and NSW to lose seats”

  1. Would this mean the seat of Stirling is reinstated in WA, or would a new seat be created elsewhere in the state, based on demographics?

    COMMENT: A new seat will be created. It is highly unlikely to be Stirling.

    1. doubtful. the new seat will be created where the population is increasing most likely east of perth between hasluck and swan given then growth is both north and south of the swan

  2. It’s not just interstate migration though, is it? Victoria has the lowest birth-rate of any State, significantly behind Qld and WA.

    COMMENT: By far the biggest factor was the immigration halt. Immigration has for many years counteracted Victoria’s loss of residents to other states and allowed the state to gain seats twice in the last decade. Differential birth rates aren’t nearly enough on their own to have an impact in three years.

  3. Will there still be redistributions in the other states even though their overall total of MPs remains the same?

    Movement within a state could make some seats deviate so they become more or less under the average.

    COMMENT: If seat numbers do not change, states undergo redistributions every seven years. A redistribution for the Northern Territory’s two seats is due to begin in February 2024 and will proceed. Tasmania is due for a redistribution in November 2024, but it will be deferred as it is within 12 months of the next election.

    1. not until they are triggered and most of the others will be within 12 months of the next election so will be deferred until august 2025

  4. What seat is likely to be abolished in nsw.

    COMMENT: I’ve had other commitments for the last few days but will publish something on the redistribution in NSW later this week.

    1. Ben, I had a look at enrolment numbers and the seats most under quota are located in the northern beaches and also middle ring suburbs of Sydney.

  5. Not long until we find out what seats are going to be abolished in nsw and Victoria and the new seat that will be created

    COMMENT: The announcement that seats will be abolished or created could be made as early as today. But which seats are involved will not become clearer until draft boundaries are released next year.

  6. With the media reporting a possible early double-dissolution election, how would an early election affect the redistribution process? Would the process be deferred to after the early election?

    COMMENT: These redistributions are another reason why a double dissolution is unlikely. The three states must elect the new number of members. If an election is called before new boundaries are drawn, NSW and Victoria will see the two lowest enrolment adjacent seats merged into one. WA would see the two adjacent highest enrolment seats split into three seats. The process is called a mini-redistribution and has never been used.

  7. I’m curious as to if there can be changes to seat boundaries in the absence of a change in overall seat numbers. Mainly because of the situation in Queensland where seats in the Northern outer suburbs of Brisbane, Moreton Bay Region and Sunshine Coast hinterland are over quota. Notably Petrie, Longman, Fisher, Fairfax and Blair to the West. All the while with the exception of Griffith and Brisbane most seats in Brisbane are under quota. I wonder if the provincial and outer suburban seats would have to shed their voters south and if this could possibly contribute to Dickson becoming more vulnerable to Labor at the expense of Longman and Petrie becoming much more difficult for Labor to win with Longman losing the Labor areas around Kallangur, Burpengary and Narangba to Dickson and Petrie losing Bald Hills to Dickson and Bracken Ridge to Lilley.

    COMMENT: If a state or territory’s seat entitlement changes a redistribution gets underway at once. Otherwise a redistribution takes place every seven years. The NT’s two seats will undergo a redistribution starting in February. The seven year redistribution rule will apply to Tasmania and Queensland shortly before the next election is due, but will be deferred because redistributions can’t take place in the last 12 months of a term. Tasmania and Queensland will undergo redistributions after the next election though Queensland may be deferred if population growth indicates it will be allocated a 31st seat.

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