Hamilton-Smith considers SA Libs alliance

South Australia Liberal defector Martin Hamilton-Smith says he will consider supporting his former Liberal colleagues if he's re-elected at the next state election.

If he holds the balance of power after SA goes to the polls in 2018, the defence industries minister says he'll negotiate with both parties.

Mr Hamilton-Smith is a former Liberal leader who defected to become an independent cabinet minister in the Labor government in 2014.

"My agreement with the premier runs until the date of the next election in 2018 and after that time it's a fresh start," he told AAP on Wednesday.

"Should I be re-elected, I'm open to supporting the Labor or Liberal party depending on who wins the largest number of seats and offers the most stable government and who takes the best policies to the election."

Premier Jay Weatherill said he was not concerned by his minister's comments.

"You can understand where he came from. He used to be the leader of the Liberal Party," he told reporters.

"It's not so surprising that in the circumstances of an unstable parliament, he would make a choice about going with the most stable option.

"If that was ever to be the case we'd be there putting our case. But it wouldn't surprise me if he made his own mind up."

Mr Hamilton-Smith's admission followed evidence to an electoral boundaries inquiry where he said the Liberals' flawed campaigning was to blame for its 14 years in opposition.

They want a redistribution of boundaries after failing to form government since 2002 despite winning a majority of the two-party vote in at least three of the past four elections.

"No matter what they do in regards to electoral boundary redistribution, they can't deal with under prepared or poor marginal seat campaigning, a lack of a party platform, a lack of imaginative, broad and visionary policies and a raft of other internal issues," Mr Hamilton-Smith said.

Opposition Leader Steven Marshall declined to comment.