Covid19 Set to Change State Representation After 2022 Election

The closure of Australia’s international borders in early 2020 has had a major impact on Australian state and territory population trends. These will play out politically in mid-2023 when the Australian Electoral Commissioner determines how many House of Representatives seats each state will be entitled to for the 2024/25 election.

The rules under which the Electoral Commissioner makes a determination are tightly defined in law and based on Australian Bureau of Statistics (ABS) population statistics. The Commissioner merely applies the Parliament’s formula and has no room for personal choice.

The ABS’s most recent population estimates for March 2021 were released last week. Based on these, the next term of Parliament will see Victoria lose the 39th seat it has gained for the coming election. On the 2021 numbers, there are no other changes to state representation, though future growth could see Western Australia on the cusp of recovering the 16th seat it recently lost.

The 2022 election will be contested on seat numbers set by the Commissioner’s last determination in July 2020. The new electoral boundaries were finalised in August 2021. My comment on Victoria losing a seat will not be relevant until mid-2023 when the next determination is made.


The Commonwealth Electoral Act requires that a determination of state and territory representation be made twelve months after the first sitting of each new House of Representatives. This allows time for any required redistribution to take place before the next election.

The determination begins by calculating a quota, done by dividing the population of the six states by twice the number of state Senators. The population of the territories and number of territory Senators are not included in the formula. With the current Senate having 72 state and 4 territory Senators, the quota equals the total population of the states divided by 144.

Each state’s population is then divided by this quota to produce a quotient. The whole number part of the quotient determines how many members each state is allocated. Any state where the remainder or decimal part of the quotient is greater than 0.5 is allocated an extra seat. The Constitution guarantees all original states five House seats, so Tasmania is always allocated five seats rather than the three delivered by the formula.

The same quotient calculation is applied to the ACT and Northern Territory, but as of this year, a different threshold is applied for allocating an extra seat. If the quotient for a territory is above 1.33 then two seats are allocated. If the quotient is above 2.4, a third seat is allocated.

New Calculations

The table below sets out the quotients and allocated seats for each state and territory according to last year’s seat determination, and my calculations for 2021 based on the ABS population statistics released last week.

Allocation of Seats to States and Territories – 2020 Determination and 2021 Estimate

Quotients Seats
Jurisdiction 2020 2021 2020 2021
New South Wales 47.3200 47.1144 47 47
Victoria 38.5487 38.2639 39 38
Queensland 29.7327 29.9638 30 30
Western Australia 15.2957 15.3997 15 15
South Australia 10.1960 10.1965 10 10
Tasmania 3.1124 3.1193 5 5
Australian Capital Territory 2.4897 2.4851 3 3
Northern Territory 1.4332 1.4793 2 2
National .. .. 151 150

Note: Tasmania guaranteed 5 seats as an original state. 0.5 extra seat formula does not apply to the territories. 2021 calculations based on ABS population statistics for end of March 2021, published 16 September.

There are three components to population growth –

  • net natural growth from births and deaths
  • net immigration from overseas arrivals and departures
  • net interstate migration

In recent decades, NSW and Victoria have gained more from immigration than other states, offsetting interstate migration out of both states. The collapse of immigration has stopped the inflow to NSW and Victoria at the same time as interstate migration has continued. Victoria is the one state with consistent outflow at the moment where NSW has stabilised.

Victoria only just qualified for a 39th seat at last year’s determination, so losing population calculates as a future loss of that 39th seat. Victoria’s quotient has slipped below the 0.5 threshold, falling from 38.5487 to 38.2639.

The only other state close to changing numbers is Western Australia, its quotient rising from 15.2957 to 15.3997, and WA could pass 15.5 by mid-2023. So it is entirely possible that the Victorian and WA changes brought about by the 2020 determination will be reversed in 2023.

More Information

I wrote a number of posts last year on the allocation of seats to states and advocating reform of the formula as it applies to the Territories. My explanation of the allocation to seats to states can be found in this post.

I also published a post on the Electoral Commissioners determination in July 2020.

I also wrote a post concerning the government’s decision to change the formula used to allocate seats to territories, resulting in the Northern Territory retaining its second seat.