The Electoral Districts Boundaries Commission today released a draft report which proposes changing the boundaries of 21 of the 47 Lower House seats for the 2026 state election – a move that would shift 44,747 voters into new electorates.

But the draft redistricting, which will be finalised in November, largely shies away from altering the boundaries of South Australia’s marginal seats, a path the Liberal Party urged the commission to take to promote a “more vibrant” state election in 2026.

No changes have been proposed to Labor’s marginal seats of Elder, Davenport, Waite, Newland, Dunstan or Adelaide.

Labor MP Sarah Andrews’s margin in her southern suburbs seat of Gibson would be narrowed by 0.2 points to 2.4 per cent under a minor change proposed by the commission.

But fellow Labor first termer Rhiannon Pearce would benefit from a redistricting in her northeastern seat of King that bolsters her margin 2.7 points to 5.7 per cent.

If the 2022 state election result was replicated in 2026, the Labor Party would be expected to hold 27 seats to the Liberal Party’s 20 under the draft boundaries.

The projected election results under the draft boundaries if the 2022 election result was replicated. Image: EDBC

“Apportioning the 2022 election Labor/Liberal two-party preferred figures to the 2026 projected elector population results in a 55.0 per cent Labor Party to 45.0 per cent Liberal Party outcome,” the commission’s draft report states.

“On that basis, the Liberal Party should expect to win 24 electoral districts and form government if it achieves a 5.1 per cent swing.”

However, the commission counts Kavel, held by Independent MP and current cabinet minister Dan Cregan, as a notional Liberal seat, along with those of other ex-Liberals Nick McBride, Troy Bell, and Fraser Ellis.

Independent MP Geoff Brock’s seat of Stuart is also counted in the Liberal column under the commission’s methodology. The replicated 2022 result also puts Dunstan – won by Labor at a by-election in March this year – in the Liberal column on a 1 per cent margin.

Under a 50/50 statewide split of the vote, Labor would be expected to win 24 seats to the Liberal Party’s 23.

How the seats would fall under a 50/50 split of the vote. Image: EDBC

In this scenario, Newland (0.1 per cent), Elder (0.7 per cent), King (0.7 per cent) and Adelaide (2.1 per cent) would be Labor’s most marginal seats, while Davenport, Waite and Gibson would fall in the Liberal column.

The boundaries commission is an independent body tasked with redrawing the state’s election map two years after each state election.

This year’s commission, chaired by Supreme Court judge Anne Bampton, opted for a path of “minimal disturbance” after significant changes to the electoral map were made in the 2020 and 2016 redistrictings.

The most significant geographic change proposed this year is the reunification of Port Augusta within one electorate after the city was split across two electorates – Giles and Stuart – by the last boundaries commission.

South Australia’s current regional electoral map, which spreads Port Augusta across Giles and Stuart. Image: EDBC

The new regional boundaries proposed for 2026, with Giles significantly shrunk but incorporating all of Port Augusta. Image: EDBC

The commission has proposed putting all of Port Augusta into Giles.

The seat, currently held by Labor MP Eddie Hughes, would then shrink significantly so it is within the commission’s tolerance for electorate population size, losing the APY Lands to Flinders (held by Liberal MP Sam Telfer) and Coober Pedy, Roxby Downs, Andamooka and Oodnadatta to Brock’s seat of Stuart.

The changes, while significant geographically, only shrink Hughes’s margin from 21.1 per cent to 17.4 per cent, meaning it would remain among Labor’s safest seats in 2026.

Brock’s Stuart would also gain Burra, Jamestown Spalding, Hallett and Farrell Flat from Liberal MP Penny Pratt’s seat of Frome. The changes will likely make Stuart – lost by former Liberal Deputy Premier Dan van Holst Pellekaan at the last election – more winnable for the Liberal Party in 2026, depending on whether Brock recontests.

The Adelaide Hills are also earmarked for change, with Cregan’s seat of Kavel proposed to lose Lenswood, Forest Range, Balhannah and Oakbank into neighbouring Heysen, held by Liberal frontbencher Josh Teague.

The commission’s pendulum indicates this would make Teague’s seat slightly safer, although the impact of the Greens – who are targeting Heysen in 2026 – is unclear in the calculations.

The commission said in its draft report that it was “appropriate to have regard to the principle of electoral fairness and the existing boundaries” in its proposed redistricting.

“The Commission considers the existing boundaries, together with the principle of minimal disturbance, are relevant and an appropriate starting point,” the report states.

ABC elections expert Antony Green said the Liberal Party and new Opposition leader Vincent Tarzia “have a mountain to climb to win the next election”.

In a blog post analysing the commission’s draft boundaries, Green noted that five Labor marginal seats would be held on margins between 5 and 10 per cent, up from only three seats under the current boundaries.

“The new electoral pendulum is so lopsided that even if things went wrong for the Malinauskas government between now and 2026, there could be a repeat of Labor’s 2010 win when the party shed a huge number of votes in its safe seats while clinging on to the marginals,” Green wrote.

“Labor has 20 seats on margins above 10 per cent. You need 24 seats for majority government in the SA House of Assembly.”

Liberal Party state director Alex May said in a statement: “The Liberal Party will consider the draft report over the coming weeks and respond to proposed boundary changes as part of our next written submission.”

Labor Party state secretary Aemon Bourke said in a statement: “The Commission has taken a minimal disturbance approach for the draft boundaries.

“The Party will be spending coming days looking over the detail of the Commission’s draft report.”

The commission will take another round of written and oral submissions from the parties before gazetting its final decision in November 2024.