THE final result of the Port Adelaide by-election may not be finalised until Saturday, when final preference votes are distributed.

Premier Jay Weatherill yesterday all but declared a win for Labor candidate Susan Close, but was reluctant to claim outright victory.

Mr Weatherill said Labor had "retained" two seats - Port Adelaide and Ramsay - and he was pleased to introduce "what appears to be two new Labor members" in Dr Close and Ramsay winner Zoe Bettison.

However, when Dr Close was asked yesterday if she was claiming a win in Port Adelaide, she said no.

At latest count yesterday, Dr Close held 53.2 per cent of the vote on a two-candidate-preferred basis.

Her nearest rival, independent candidate and Port Adelaide mayor Gary Johanson, sat on 46.8 per cent.

Electoral Commissioner Kay Mousley said about 1500 postal votes would be counted today and preferences would be distributed on Saturday.

Mr Johanson was in no rush to concede defeat.

"At this stage, I would say the numbers probably favour the government, but I'll prolong the agony," he said.

However, even if Labor won the seat, it had lost the support of the people, he said. "It's hard to see that as a victory," he said.

Mr Johanson confirmed he planned to run again as an independent candidate in the 2014 general election.

Mr Weatherill conceded Labor's popularity had fallen "extraordinarily" since the 2010 election and said it would be a "long, hard process of rebuilding".

At a Caucus meeting of Labor MPs yesterday, Mr Weatherill outlined the party's agenda before Parliament begins tomorrow.

Meanwhile, Liberal leader Isobel Redmond stood by her party's state executive decision not to field candidates in either by-election.

"The best chance for anyone else to win other than Labor was for us not to run." Ms Redmond said. She described the Port Adelaide result as a "resounding statement by the people that they've lost faith in this government".