Federal focus worked in Fisher: new MP

Newly elected Labor MP Nat Cook says it was appropriate to campaign on federal issues in the Fisher by-election because voters are worried about job security.

Ms Cook secured a stunning win for Labor in the southern suburbs seat after a recount narrowed her lead over Liberal candidate Heidi Harris to just nine votes.

Her win gives the Weatherill government 24 lower house seats, meaning it will be able to pass legislation without the support of independents.

Ms Cook's victory, in a seat considered to be safe Liberal territory, has been attributed partly to a strong Labor campaign on federal issues.

Labor zeroed in on Abbott government cuts to health spending and uncertainty about future submarines, amid comments by Defence Minister David Johnston that he would not trust Adelaide shipbuilders to "build a canoe".

Ms Cook said Labor's campaign had resonated with voters who were worried about the impact of federal spending cuts.

"We needed to show that we as a government will work forward as really strong advocates against federal policy that hurts our community," she told AAP.

"The community were telling us that they didn't feel that the (state) Liberal Party were standing up against those federal issues."

Ms Cook, a prominent anti-violence campaigner whose son died in a one-punch attack in 2008, said she was relieved to have had her victory formalised.

Independent candidate Daniel Woodyatt is considering a legal challenge against the result after the electoral commission found the Liberals had distributed misleading campaign material about him.

The Liberals have turned their attention to a January 31 by-election in the neighbouring seat of Davenport, which they held with an eight per cent margin at the March state election.

Opposition leader Steven Marshall said the Liberals would continue to campaign against unpopular state budget measures.

"The Labor Party ran a very effective but spurious fear campaign (in Fisher) against work leaving South Australia," he told reporters.

"It was a very disappointing result but we're not going to be broken by it."