Victorian Federal Redistribution using Updated Enrolment Data

Last October, eagle eyed observers spotted that there was something wrong with enrolment projection data for Victoria released by the Australian Electoral Commission (AEC). The projections were released as base data for the looming federal redistribution to remove one of Victoria’s 39 seats in the House of Representatives.

A 2023 decision by the Australian Electoral Commissioner under Section 24 of the Constitution had determined that NSW and Victoria would lose House seats and Western Australia gain a seat. The size of the House of Representatives for the next election will be reduced from 151 to 150 seats. I wrote a post at the time explaining the decision.

Victoria had gained an extra seat at each of the two previous elections. Both had been created in western Melbourne, Fraser before the 2019 election and Hawke ahead of 2022. The redistribution creating Hawke had been based on population data from before the 2020 arrival of Covid. With overseas immigration halted for two years, and internal migration to the outer states continuing, Victoria’s population declined relative to other states over the three intervening years.

But removing a seat won’t simply be a matter of abolishing Hawke or Fraser. As the projected enrolment data released last week shows, population growth in Melbourne’s north and west is faster than in Melbourne’ east and south-east. A seat must be abolished in Victoria and the corrected projected enrolment data indicates strongly that a seat will be abolished in Melbourne’s east.

The first projected enrolment data released last October had been prepared by the Australian Bureau of Statistics (ABS) for the Australian Electoral Commission (AEC). The data was flawed in applying a uniform growth rate across the state. The corrected enrolment projections released by the AEC last week now have growth rates that vary across the state.

(Happy to post comments with people’s suggestions on where the changes will occur.)

A Quick Recap of Redistribution Rules

Redistributions redraw boundaries to ensure that a state’s electoral divisions have roughly equal enrolments. Quotas are calculated by dividing state enrolment by the number of divisions to be drawn. Two quotas are used for federal redistributions, one based on current enrolment at the redistribution’s start date, 9 August 2023, and a second based on projected enrolments set for 17 April 2028.

Current Victorian enrolment is 4,441,980 giving a quota for 38 seats of 116,894, around 3,000 electors more than for the current 39 seats. All 38 new divisions must be drawn with enrolments within 10% of this number. The 39 current electorates are spread between 4.0% under quota and 6.7% over.

Projected enrolment is 4,835,048 giving a projected quota of 127,238, around 3,250 electors more than for 39 seats. The projected quota tolerance is tighter than for the current enrolment and all divisions must have projected enrolments within 3.5% of the quota.

Using the newly released projections, 30 division are under quota, 23 under by more than the permitted 3.5% variation. Only nine divisions are over the projected quota, six by more than 3.5%. Variations range from 10.8% under in the eastern Melbourne seat of Aston, to 13.4% over in the south-west Melbourne seat of Lalor.

The quota restrictions must be applied in drawing the boundaries, but within these limits the Redistribution Commissioners can take account of –

  • community of interests within proposed districts, including economic, social and regional interests
  • means of communication and travel within the proposed district
  • the physical features and area of the proposed district
  • the boundaries of existing districts

Regional Victoria

The 10 seats that can be classed as regional and rural, running clockwise from Corio to Monash, contain 9.76 projected quotas worth of voters and will need to nibble at the edges of Melbourne to maintain 10 seats.

The map below colour codes all 39 divisions based on percentage above or below the 38 seat projected quota. The five seats shown yellow (Mallee, Ballarat, Indi, Monash and Gippsland) are below quota but above the 3.5% permitted variation and therefore not required to change, though alteration is likely to accommodate the four seats in brown that are below the 3.5% permitted variation, Wannon (-6.2%), Corio (-8.1%), Bendigo (-4.9%) and Nicholls (-5.6%). Only Corangamite (+8.7%) in green is over the permitted quota variation and needs to shed voters. On Melbourne’s fringe, La Trobe (+9.8%) to the east and McEwen (+6.4%) to the north are also over the permitted variation.

You can use this map to drill down and look at Melbourne seats, but a more useful Melbourne-only map is included and discussed further down this page.

When Victorian electoral boundaries are redistributed, the first seats drawn tend to be those in the state's corners, Gippsland, Indi, Mallee and Wannon. The first three named seats don't require change, but may have minor changes to deal with boundary adjustments closer to Melbourne.

Wannon and Corio must gain voters and over-quota Corangamite in between will be fought over for surplus. The northern and eastern boundaries of Corio coincide with the City of Greater Geelong and in the past it has been unusual to push north-east beyond Little River into Werribee. More likely is that Corio would gain voters from Corangamaite with probably some surplus left over to help Wannon. The boundaries of Ballarat and Mallee could come into play on these changes.

Bendigo (-4.9%) and Nicholls (-5.6%) must grow. Parts of McEwen (+6.4%) could be transferred to a northern division, or western parts of Hawke (+0.9%) around Ballan and Bacchus Marsh could be transferred back into Ballarat with the created surplus flowing through to Bendigo and Nicholls.

Every excision from Hawke and McEwen helps create a shortfall in Western Melbourne. The Commissioners may look at addressing enrolment shortfalls in the state's east by transferring areas out of La Trobe (+9.8%) and engaging in major surgery to Casey (-6.6%) in Melbourne's outer east.

Tweaking in regional Victoria is unlikely to have significant political impact apart from Corangamite. The political story of the redistribution is more likely to unfold in Melbourne.

Abolish a Melbourne seat - east or west of the Yarra?

The map below colour codes variation from the projected quota and shows clearly that outer suburban seats are over quota while the older core of Melbourne is largely under quota. The scale from light to dark green shows increasing surpluses, shade from yellow to dark brown showing increasing enrolment shortfalls. You can hover over the map to see the variation for each division.

Three divisions in Melbourne's north and west are well over quota, Lalor (+13.4%), Calwell (+10.2%) and McEwen (+6.4%), along with Holt (+6.2%) and La Trobe (+9.8%) in the outer south-east. Six seats north of the Yarra are between 3.5% and 10.0% under quota compared to 12 in the east and south-east with the same shortfall, along with Aston at 10.8% under quota.

There are 13 seats north and west of the Yarra, and while current enrolments put the area half a seat under quota, the projected enrolments show there are enough voters for 13 seats without a significant crossing of the Yarra. But if parts of Hawke or McEwen are transferred to regional seats, the west starts to fall short of 13 seats.

East and south-eastern Melbourne has 16 seats but the enrolment projections sum to only 15.3 quotas, even lower if parts of La Trobe or Casey are transferred to a regional seat. It is hard to see any other option than a seat being abolished in Melbourne's east.

The redistribution is going to be a cross between a jigsaw puzzle and playing a giant game of pass the parcel. From wherever the Redistribution Commissioners start drawing boundaries, they will progress inland like a bulldozer, building up enrolment surpluses like piles of soil.

Port Phillip Bay and the lower course of the Yarra tends to be the starting points for drawing boundaries. East of the Yarra, this sees Macnamara (-4.0%), Higgins (-8.3%), Kooyong (-4.5%) and Goldstein (-6.5%) drawn first. The Commissioners could choose to abolish Higgins as a seat squeezed between the other three, solving the eastern shortfall and leaving an enrolment surplus to distribute eastward. Or perhaps it will be Macnamara abolished with Higgins and Goldstein sliding into the void left.

Or Higgins could be retained by slipping east, which has significant implications for the political complexion of Macnamara. Keeping Higgins makes it more likely one of the following could be for the chop - Chisholm (-5.8%), Menzies (-5.5%), Deakin (-6.9%), Casey (-6.6%), Hotham (-0.2%), Isaacs (-5.6%), Aston (-10.8%) or Bruce (-6.4%). Geography means that the shortfall in Dunkley (-7.5%) and Flinders (-6.6%) will probably be solved by the surplus from Holt (+6.2%) and La Trobe (+9.8%).

Being so far short of quota suggests Aston could disappear, except that its boundaries match exactly the City of Knox council area. Aston's western boundary following the Knox council boundary along Dandenong Creek is strong based on geography and community of interest. Pushing boundaries north into Deakin or east into Casey would solve Aston's shortfall, but put both of those seats into play for abolition.

Which raises another point about naming divisions. Given Alfred Deakin's role in Federation, as a three term Prime Minister, and as founder of the first Liberal Party, abolition of a seat named after him would be unlikely. But nothing would stop another seat such as Chisholm or Casey being re-named in his honour.

And given the desire to have more names commemorating women and fewer named after 19th century Governors, Hotham could end up disappearing and being re-named Chisholm.

The abolition of Casey could see the eastern and of Deakin combined with the upper Yarra Valley while areas in the Dandenongs move into Aston and La Trobe. La Trobe would have to shed electors, but that could be accommodated by rural Monash and divisions in south-east Melbourne.

The new projected enrolments make the Liberal Party's proposal to cross the Yarra at the CBD and extend Melbourne to Port Phillip Bay look highly unlikely. Labor's proposal to push McEwen across the river and into the upper Yarra valley is no longer required but may yet be implemented in part along the northern boundary of Menzies and the current Casey.

Assuming the metropolitan south-west boundary with the City of Geelong is not crossed, the surplus of Lalor (+13.4%) would boost Gellibrand (-1.9%) with surplus to boost Fraser (-5.8%) and Maribyrnong (-8.9%). Wills (-6.0%), Cooper (-6.4%), Jagajaga (-6.7%) and Scullin (-4.3%) all need to expand. Calwell (+10.2%) has a significant surplus to boost other seats.

Gorton (+1.8%) and Hawke (+0.9%) don't need significant change, but there is a strong possibility that Hawke could lose Ballan and Bacchus Marsh to Ballarat, and McEwen (+6.4%) could lose enrolment to several under quota non-metropolitan seats. If Hawke or McEwen shed enrolment to non-metropolitan seats, it makes it more likely that a seat mainly based north of the Yarra would have to cross the river. As noted earlier, this could be McEwen at its eastern end.

Gellibrand might be up for a name review, and a name change has been suggested by Labor, but its current position makes it likely the seat will be retained even if its name is changed.


In my original analysis based on current enrolments and the originally released incorrect projections, I said the redistribution was a choice between abolishing a western seat and rotating electorates clockwise, or abolishing a seat in the east and rotating seats anti-clockwise.

The corrected projections make this much less likely. It seems hard to come up with a scenario where anything other than a seat in Melbourne's east is abolished.

The political implications of the change are difficult to assess. The band of seats I have mentioned as possible abolitions are marginal, some Labor and some Liberal. The margins in Labor's core seats look set to be left largely intact, leaving a scramble in eastern Melbourne as the boundaries of more marginal Labor and Liberal seats are re-arranged.

Submission to the Redistribution Commission

Submissions and comments on the submission have closed. I previously wrote a post looking at what the major participants proposed.

The Commission has not proposed to re-open submissions and comments, but some of the original submissions have been rendered irrelevant by the newly published data. The general thrust of the submissions remains even if the fine detail is no longer correct.

8 thoughts on “Victorian Federal Redistribution using Updated Enrolment Data”

  1. Thanks for the update . It is going to interesting to see how this all pans out. Fun and games and possibly fear and loathing will develop within the major political parties

  2. I do feel it is wrong for the AEC to continue on and not restart the redistribution process.

    The ‘bad’ original figures has just made most people’s Suggestions and Comments worthless, meaning the AEC will decide the boundaries with effectively no input from the public.

    They’ve justified it by saying that there’s still the Objection stage, but it’s not always easy to reverse decisions after they’ve already been made.

    1. I think that, really, the main point of redistributions is to have local people send to the AEC, what is good for them. So that the AEC can take their needs into account as they redraw the electoral boundaries. We’ve heard what those people want, and those wishes can still be taken into account. The only other thing would be that the submissions which tried to perform the redistribution themselves, most of which come from parties, whose main goal in this affair is not really to advocate for their local community specifically, but to put ideas into the committee’s head so that the redistribution will be a bit more favorable for them.

      If anyone feels as though their communities needs would be violated by the redraw, then let them use the Objection stage, that is what it is there to do, but if not, letting the AEC have the final, impartial say on who lives in what electorate is what we, as taxpayers, pay them to do.

  3. Agree Mark, for the NT redistribution which suffered from a similar ‘oversight’ error they allowed a fresh round of submissions.

    Maybe to speed up the process they could have a single round of submissions (suggestions and comments) rolled into one instead of the standard two round process.

    COMMENT: The NT redistribution was a different issue. Notices had not been gazetted so the redistribution was not conducted lawfully. They had to start the process again, though as the redistribution had gone through all previous stages, they were able to do the second redistribution more quickly.

    The NT redistribution also updates its enrolments at every stage of the process making it the only redistribution that doesn’t set a fixed quota at the start of the process.

    1. The nt problem was due to an error in following the law and the law required them to restart the process. The problem is if they restart the process it may not finish in time for the next election

  4. Given the lack of liberal seats in inner Melbourne its hard to see how they will not be given a leg up by the radical surgery required. Disrupts a lot of sitting (mostly ALP) members, makes the Teal’s job harder and may even recreate some marginal Libs if Higgins loses Prahran…

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