Could a fracture in conservative politics cost right-wing parties a seat in SA's parliament?

There is little doubt that we will be looking at a sea of red across South Australia's 47 lower house electorates when election results roll in from 6pm on Saturday.

But how Labor Premier Peter Malinauskas uses his power, and who he has to negotiate with, will be determined by the much tighter election contest underway for the state's upper house.

The race for the Legislative Council sees incumbent members in the fight for their political lives trying to fend off the threat of a surging One Nation and the Labor Party trying to grow its numbers.

With voters seemingly fraying between the Liberal opposition, One Nation and other minor parties, there is a tussle happening on the right for the final spots in the chamber.

Depending on how the chips land it could result in the collective conservative side of politics losing out on a seat.

The balance of power — and Mr Malinauskas's ability to get his second-term agenda through parliament — is on the line.

The upper house has been a handbrake on successive governments, and, in this term of parliament Mr Malinauskas was unable to get his revamp of planning laws through the upper house with the Liberal Party and Greens both opposed.

Will he soon have a more amenable parliament to work with?

Long odds for Labor takeover

The Legislative Council has 22 members serving staggered eight-year terms, and half of them face election every four years.

For five decades no government has held a majority in the chamber, but Labor is currently in its strongest position in years.

In 2022, Labor won five seats for the first time since 1989 which gave the government a total of nine votes, three votes short of a majority.

When parliament resumed, Labor and the Greens backed Liberal MLC Terry Stephens to be Legislative Council president — a role he had previously held but relinquished in 2020 over the Independent Commissioner Against Corruption's investigation into his use of parliamentary allowances.

The decision gave Labor an extra vote on the floor, meaning it only required the support of either the Greens or SA Best members to pass legislation.

If Labor does grow its upper house vote in this election it stands a good chance of winning five seats again this year, increasing its total number of votes by one and improving its negotiating position.

The political career of Primary Industries Minister Clare Scriven is also on the line because she has been bumped down to fifth position on the Labor ticket.

If the government does not gain a seat in this election she is out of a job.

Winning a sixth would be a stretch — Labor would likely need an upper house vote in the mid 40s to have a shot — and such a feat has not been achieved since 1975.

A quota for election is 8.3 per cent, so barring a cataclysmic wipe-out for the Liberal Party, both Liberal MLCs seeking re-election — Ben Hood and Heidi Girolamo — should be easily returned.

With polls indicating the opposition is losing votes in several directions it is less certain if the party will win any more.

Minor parties in major scuffle

In 2022, the first One Nation candidate was elected to South Australia's party — Sarah Game, who has since defected and formed her own namesake party.

But with the party's improved position in polling its lead candidate, Cory Bernardi, would be expected to win a seat, and he could be joined by Victor Harbor councillor and construction business operator Carlos Quaremba.

The Greens have consistently won one seat in the upper house since 2006 and we would expect its lead candidate Melanie Selwood to win election.

From there things get much more uncertain.

The final one or two seats may end up a complicated battle between the Liberal Party, One Nation, and a collection of other minor parties and independent candidates.

Independents Tammy Franks (a former Greens MLC) and Jing Lee (a former Liberal MLC) are both chasing re-election, but face a tough battle to retain their seats.

This election could also spell the end of SA Best's Connie Bonaros who is campaigning hard for re-election and has been taking up the fight to Cory Bernardi and One Nation.

She entered parliament eight years ago as one of two SA Best members elected at the peak of the party's support.

If she is defeated it will represent the extinguishing of the Nick Xenophon-founded political party in South Australian politics.

Former footballer Chris McDermott's chances of winning a seat with Sarah Game's Fair Go For Australians party were dealt a serious blow last week when he abruptly quit the party, and Sarah Game urged voters to back the Liberal Party instead of her own outfit.

Former Family First senator Bob Day is also running for the upper house with his Australian Family Party, adding to the long list of former Liberal members contesting this election with other parties.

Other right-wing minor parties on the ballot include the Nationals, Family First, and Mark Aldridge's United Voice Australia party.

Many of those parties are contesting seats in the lower house as well, seemingly to boost their name recognition for the upper house.

It does not matter so much in the lower house, where voters are required to preference every single candidate, but in the upper house most South Australians do not number past their first choice of party above the line.

The risk for the conservative side of politics is that all those minor parties split enough of the vote to cost the right the final seat.

The result in those final seats will likely take weeks to settle.

With all the ballots that need to be counted and checked we are unlikely to know the full make-up of the chamber until at least mid-April.