South Australian senator Rex Patrick has confirmed he will recontest his upper house seat at the federal election.
It means he will go up against former colleague Nick Xenophon, who announced last week he would also run as an independent in the Senate.
Senator Patrick had previously said that should that happen, he would step aside and run for the federal seat of Grey.
But he said that plan was now untenable.
"I'm now in a position where it's very difficult to run for Grey, even though I think they deserve a strong representative in the House [of Representatives]," he said.
"Nick will unfortunately have to run with his name below the line and that makes it very difficult for him."
Senator Patrick replaced Mr Xenophon in the Senate in 2017 when the latter made an unsuccessful return to state politics.
In 2018, Senator Patrick and other federal MPs associated with Mr Xenophon formed Centre Alliance, which Senator Patrick then left in 2020 to become an independent.
In January, Senator Patrick declared he would definitely run for the Senate; however, last week he said Mr Xenophon's re-emergence had "changed the political landscape".
He said today that Mr Xenophon's run risked splitting the minor-party vote that could then go to One Nation or Clive Palmer's United Australia Party.
Mr Xenophon said he would be running in a group with the only remaining Centre Alliance senator — Stirling Griff — so they will be able to attract above-the-line votes, despite Senator Patrick's assertion.
Mr Xenophon blamed Senator Patrick for diminishing the crossbench power he had built up in federal parliament.
"As a team, we did a lot of good things, and then Rex left the team and that really crippled the ability in the Senate to achieve good things in South Australia," Mr Xenophon said.
Independent considering run in Grey
Liberal whip Rowan Ramsey has held Grey since 2007, most recently with a 13.3 per cent margin in 2019.
The seat covers 92 per cent of South Australia, including everywhere north of the Barossa Valley and the Riverland.
Independent Liz Habermann, who came close to seizing the Liberal Party's safest seat, Flinders, in the state election, said she was now considering running in Grey.
The Wudinna Bakery owner and euthanasia advocate had previously considered running for Grey, but chose to run in Flinders first after consulting Senator Patrick.
After conceding yesterday, she said it was too soon to fully decide on Grey since she was still recovering from the state election.
"It will take me a while to recover from that both physically and financially, but I know that time is ticking away and that federal election is very, very close, so I think by the end of the week I will have decided," she said.
Tumby Bay Mayor Sam Telfer won Flinders with a 3.4 per cent margin for the Liberal Party in the state election.