ACT Assembly going to 25


In the lead-up to the state elections in South Australia and Tasmania, I didn’t have time to cover another electoral story in the Australian Capital Territory. After many years of debate, and competing proposals, the ACT Legislative Assembly appears set to increase in size, from 17 to 25 seats.

The ACT’s legislative body currently has 17 members elected from three multi-member electorates. The electorate of Molonglo, centred on Lake Burley Griffin, elects seven members, while the Belconnen-based Ginninderra and the Tuggeranong-based Brindabella each elect five members.

The Labor Party and the Greens have supported some expansion in size of the ACT for a while, but it has faced opposition from the Liberal Party.

An expert panel (read the report) recommended the creation of five electorates – which would initially elect five members each before eventually electing seven members each for a total Assembly size of 35.

The Liberal Party’s ACT division decided to support the increase to 25 at their meeting on March 5. It’s unclear if either party is pushing for an eventual increase to 35 seats.

The next ACT election is due in just over two and a half years, giving plenty of time for the Assembly to pass the change and for new boundaries to be drawn.

We don’t know exactly how the boundaries will be drawn, but there aren’t that many options when you are drawing electoral boundaries in Canberra.

One possible way to divide ACT's polling places into five electorates. Belconnen in orange, Central in purple, North in blue, Tuggeranong in green, West in yellow.
One possible way to divide ACT’s polling places into five electorates. Belconnen in orange, Central in purple, North in blue, Tuggeranong in green, West in yellow.

In 2010, I conducted some analysis at the likely impact of a 5×5 electoral system that didn’t make it to this blog. This included assigning all polling places to one of five electorates.

The ACT is divided into seven districts. The central suburbs are split into North Canberra and South Canberra by the Lake. These areas are usually referred to as the ‘inner north’ and ‘inner south’.

In the north you find Gungahlin, and Belconnen in the north-west.

In the south you have Tuggeranong, and just north of Tuggeranong to the west of the city is Weston Creek and Woden Valley.

When drawing these boundaries I found that both Tuggeranong and Belconnen were too large to be contained within a single electorate. Both areas formed the basis for an electorate. I then created an electorate called ‘West’ covering Weston Creek and the remainder of Tuggeranong. In the north I created an electorate covering all of Gungahlin and northern parts of Belconnen, as well as the northern fringe of the inner north.

I then created a fifth electorate in the centre, surrounding the Lake and mostly covering the inner south and inner north.

Population will continue to shift, and I didn’t take into account absentee and other special votes which may vary in numbers. It’s quite possible that the Central electorate will lose parts of Woden. Having said that, I think they provide a useful guide as to how a 5×5 system would change the balance in the ACT.

I’ve taken the results by polling place of the 2012 results to produce my estimate of how many quotas each party would have polled in each of these five hypothetical electorates in 2012.


The Liberal vote is more concentrated in Tuggeranong so the highest result for a particular party is for the Liberal Party in Tuggeranong. Tuggeranong is the best area for the Liberal Party, and the worst for both the ALP and the Greens. Belconnen is best for the ALP and worst for the Liberal Party. The Greens vote peaks in the central electorate.

On these numbers, I estimate that we would see 11-12 Liberals, 10-12 Labor and 2-4 Greens MLAs. The fifth seat in Belconnen could either go to the ALP or the Greens. The fifth seat in the West could go to Labor, Liberal or Greens. In this scenario, all parties would increase their numbers.

In most circumstances, this result would ensure that both major parties won two seats in each electorate. The Greens vote is quite strong in Central – probably enough to offset the fact that they previously benefited from a lower quota in Molonglo that has been lost. In this scenario, 0.7 quota in the North is probably enough to elect a Green, but may not be enough to guarantee a win if the balance between the major parties shifts.

The Greens polling 0.6 quotas in Belconnen and the West would provide enough of a base to give the party a chance, particularly in a good election. The Greens would have to perform exceptionally to win a seat in Tuggeranong.

Overall, these new electorates would see no change in the balance of power: on 2012 votes, the Greens would have held the balance of power, with the likely result seeing Labor and the Greens sharing government as they have done. The biggest impact would have been a deeper bench: resulting in more talent available to serve as ministers, and a larger backbench.

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  1. Interesting analysis! Strangely enough it is the same arrangement as the Tas House of Assembly.
    On a similar vein I’ve often tried to work out how a 3 or 4 electorate Tasmania would work out, if the constitutional minimum of 5 seats was removed.
    With 4 I can just assume Lyons would be split in four and there would be 2 Northern and 2 Southern based seats.
    With 3 it would be a lot trickier, as Hobart itself is about half the population. You’d end up with a “Greater Bass” covering the current Bass area and extending to the whole Tamar valley and include as far west as Devonport, Deloraine, perhaps Ulverstone; a “Greater Denison” which would absorb the southern part of Franklin (Huon/Kingston) and the rest – meaning Burnie, Bellerive and pretty much every small town and rural area across the state would be in the same electorate.

  2. Nice work Ben. While Tuggeranong was a Lib stronghold in 2012, it’s worth noting that it is usually more even or even slightly Labor leaning than those numbers suggest. Then Liberal leader Zed Seselja made a big pitch to the South for electing ‘someone from the Valley’ at the ACT election (along with a rather mendacious claim about rates tripling). With him now in the Senate, I would expect the last Tuggeranong seat to be more competitive.

  3. Wouldn’t the perfect arrangement for the ACT be one electorate with proportional reprensentation?

    In practice that woukd be a close fit with what they have federally.

  4. Is the one quota for Belconnen for “Other” mainly from the Australian Motorists Party?

    Also the Molonglo development to the west of Lake Burley Griffin is likely to mean a re-draw of the electorates.

  5. While Molongolo will see thousands of people move into Weston Creek, growth is still greatest in the North.

  6. While I don’t disagree with the analysis, it seems to be pretty right, I have to take issue with: “The ALP polled higher than the Liberal Party in 2012”.

    I’ve just checked my Electoral Compendium to confirm that the ALP polled 85991 votes or 38.88% while the Libs were ever so slightly ahead on 86035 votes or 39.90 %.

  7. It will be interesting to see how the Electoral Commission manages to balance population equity with geography – which is what community of interest comes to in Canberra. the new development at Molongolo is starting at the southern end which has transport connections and close affinity with Weston Creek.So that will probably work OK for the first distribution.

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