A major review of South Australia's electoral boundaries is underway, with the carve-up likely to play a key role in the outcome of the next state election.
SA's Electoral Districts Boundaries Commission has conducted public hearings this week ahead of delivering a new set of boundaries next year.
The latest review comes after a major shake-up in 2016, which helped secure victory for the Liberal government in 2018.
That shifted almost 400,000 voters into different seats and nominally delivered four seats to the Liberals.
It was based on a so-called fairness clause designed to ensure that the party which won the statewide popular vote would also win enough seats to form government.
In 2017, the then Labor government successfully scrapped the fairness clause in voting legislation, and a move by the new government to bring it back also failed in the parliament earlier this year.
Now Labor has told the boundaries commission it no longer has a mandate to ensure the objectives of the fairness principle are achieved.
Rather, Labor says the next redistribution should ensure every electorate has a similar number of voters, within a permissible tolerance, ensuring the one vote, one value principle.
This permissible margin was generally regarded as about 10 per cent.
By comparison, at the 2018 election, one Labor-held city electorate had about 25 per cent more voters than one Liberal-held country seat.
"There are sound reasons why this commission should not only pursue numerical equality but should go further in achieving it," Labor said in its submission.
But the Liberal Party argued the 2016 redistribution produced fair boundaries and said the commission should not change the methodology it applied at that time.
"The 2018 election produced results that reflected the popular will," the Liberal Party said.
"The election result is a powerful reason for the current commission to adopt the same principles and methodology of the 2016 commission.
"Any departure from that approach would risk drawing boundaries that are unfair."
The Electoral Reform Society of South Australia has also weighed into the debate, declaring the 2016 redistribution an unacceptable result and one that should not be allowed to happen again.
It backed scrapping of the fairness clause which it said would make the commission's work this time much easier.
But it also went further, calling for fundamental change in the way governments are elected in SA by the introduction of multi-member electorates and a proportional voting system similar to that in place in Tasmania.
"The society believes that only then will South Australia have electoral fairness with political parties winning their rightful number of seats based on the votes they received," it said.