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.

8 thoughts on “Covid19 Set to Change State Representation After 2022 Election”

  1. Will the seat that gets abolished in Victoria definitively be Hawke as the newest seat, or could it be any Victorian seat?

    COMMENT: It definitely won’t be Hawke abolished, though Hawke might be substantially re-drawn. One of the 39 the seats will be abolished, and I suspect it will be one in Melbourne. Pick an urban seat with no obvious boundaries. Seats like Chisholm or Hotham would be the easiest too abolish and distribute between remaining seats.

    Every rural seat will have to move towards Melbourne, outer suburban seats will move inwards, and the seats in-between the outer suburbs and Yarra River are the ones that would be squeezed. But it’s two years before any redistribution would get underway.

  2. Could the Greens gain a second Melbourne metro seat at the next election? Is it unlikely? Will the AEC abolish the seat of Melbourne in 2023 or is not realistic option?

    COMMENT: The chances of the Greens winning a second seat depends on how they poll. I doubt Melbourne would be abolished because it has strongly defined boundaries and is normally one of the first urban seats drawn.

  3. Hotham looks like a seat that should be abolished if required its a bits and pieces seat with little community of interest. If Chisholm is abolished instead then i think Hotham should be renamed Chisholm similar to what happened with Reid/Lowe was merged. Hotham is a name of British colonialist.

    COMMENT: What you are saying is the name should be abolished. As was the case recently with the abolition of Stirling, the electorate called Cowan could have been called Stirling but Cowan was retained as the name.

    To me, the new boundaries for Chisholm make it tough for the seat to survive Victoria losing a seat. By removing Koonung Creek as the northern boundary, Chisholm has lost a geographic anchor while surrounding electorates east, north and west have a clearer geography. I could easily see Menzies taking in the northern part of Deakin and Deakin slipping in to take the northern half of Chisholm. Chisholm and Hotham would then merge into one seat with leftovers shoring up the rest of eastern and south-eastern Melbourne. But there’s a couple of years before it happens.

  4. Antony, I’m aware that special legislation was passed some time ago to protect the NT’s 2nd House of Reps seat, but why does the ACT have 3 seats when it is below two and a half quotas. On your stats, the ACT’s share of the Australian population is falling, very slightly. What would it take for the ACT to go back to 2 seats, if that trend were to continue?

    COMMENT: The legislation did not save the NT’s seat. It instead changed the formulas for the two territories to use the harmonic mean as the rounding point instead of the arithmetic mean. So the rounding point for the NT became 1.33 instead of 1.50, and for the ACT 2.40 instead of 2.50. Rounding at the harmonic mean results in the territory having an average population per member closer to the national average than rounding at the arithmetic mean. The government adopted the harmonic mean on my suggestion. I set out why the arithmetic mean shouldn’t be used for the territories in this post.

  5. I’ve got to wonder if Victoria’s “outer ring” (Wannon, Mallee, Nicholls, Indi, Gippsland) of rural seats could survive in a 38-division configuration with a projection date of 2026 or 2027. Not saying one of them would be eliminated (in name), but apart from Golden Plains as a potential addition to Wannon, there’s not a lot of electors available to bring them up to an increased quota in the current configuration.

    The alternative would be the arrangement proposed in 2010, but backed away from after a swathe of objections. Namely that Mallee and Indi would divide up the northern part of Nicholls and you’d instead end up with an inland division comprising Shepparton and areas to its south, running all the way to the NE fringe of the metro. In 2010 that division was to be McEwen, with Murray (now Nicholls) abolished and a division of Burke created loosely where Hawke is now.

    The naming outcomes might be different now – with more growth on the northern metro fringe it’s possible all three names (Nicholls, McEwen, Hawke) could survive, but the concept of Shepparton in a division that extends south rather than to the Murray might be inevitable if there aren’t enough electors to patch up the existing “ring”.

    Of course, the objections from 2010 are still somewhat valid. Specifically that Murray (as it then was) represented the Goulburn-Murray irrigation district and that Shepparton was central to that region. But the argument has been weakened by Mallee already extending east into Loddon (since the 2018 redistribution) and the numerical reality may not be able to be resisted in a return to 38 divisions.

    COMMENT: If Corangamite moves into Geelong and Corio slides north and straddles the gap to western Melbourne you might solve the western districts problem. As with the state redistribution, the problem is trying to fit western seats around Bendigo and Ballarat. We don’t know the projected numbers for several year’s time. A lot of the Melbourne outer suburban enrolment numbers were based on population growth that may not occur, and the rural seats were set above quota at the redistribution.

  6. Antony, for my own clarification – is there the (admittedly slim) chance that the international border reopens fast enough and to the extent that new arrivals actually push Vic back over the threshold in time?

    COMMENT: My quick glance at the ABS data would suggest it won’t re-bound in time.

  7. Based on my calculation of seats west: east of the Yarra, it comes out at about 20.7 west to 18.3 east. This is based on current enrolments and this may change by 2023 but it does suggest that a seat will effectively need to straddle the Yarra in a similar way that Menzies did in the last cycle or the old Diamond Valley used to do. The question will be whether a western seat does the straddle and an eastern seat abolished, or an eastern seat such as Menzies crosses over and a western seat is abolished.

    To my mind, the latter would seem to make more sense and Jaga Jaga the seat to be abolished. Unless Melbourne was to cross the river and take in Southbank and parts of South Yarra (quite feasible in view of the Commissioners predeliction for LGA boundaries ), the knock on effects of having Menzies move would be substantial.

    Another unknown is whether the move to the regions is sustained or if it has occurred at all. This may see minimal changes in seats such as Monash, Indi, Corangamite, Wannon, Ballarat and Bendigo, and bigger changes in Melbourne.

  8. Will Libs or Labor likely benefit more from this?

    COMMENT: It depends where the boundaries are drawn. This won’t happen for more than two years so is a little difficult to speculate on.

Leave a Reply