Nick Xenophon might not win his own seat at this weekend's South Australian state election, a new poll shows.
But the SA-BEST leader dodged questions on the leadership arrangement of the party should he fail to pick up the seat of Hartley, where incumbent Liberal MP Vincent Tarzia leads him 51 to 49 per cent in the two-party preferred vote.
Mr Tarzia also polled the highest primary vote at 38 per cent, ahead of Mr Xenophon on 30 per cent and Labor candidate and former minister Grace Portolesi on 22 per cent.
Mr Xenophon called the contest a "two horse race" and appealed to voters to consider where their preferences will be directed.
"My message to Labor and Greens voters is that if they vote for Labor or the Greens in the seat of Hartley they'll effectively be delivering the seat to the Liberals and to Mr Marshall," he said.
He said it was premature to comment on how the party would operate should he not win the seat.
"There'll obviously need to be a parliamentary leader if I don't make it, but I'm not contemplating that," Mr Xenophon said.
"I always knew that this would be a tough battle."
The Galaxy poll commissioned by The Advertiser surveyed 590 voters last Saturday.