The woman who gave Liberal leader Steven Marshall a scare in his seat of Dunstan at last year’s state election has firmed as a Labor frontrunner to take on Christopher Pyne in Sturt.

Prominent retail lawyer Jo Chapley, whose family owns one of South Australia’s biggest supermarket chains, has confirmed she has been approached by senior Labor figures to re-enter the political fray at next year’s federal election.

“I’m giving it serious consideration,” she told InDaily.

But it’s understood even if she were to lose the battle for the eastern suburbs Liberal fortress, which Pyne has held since 1993, the campaign could set her up for another tilt at Dunstan, which Labor insiders consider vulnerable despite being held by an incumbent Opposition Leader.

“The seat of Dunstan is definitely vulnerable,” a senior source insisted.

But other party figures are reluctant to push her for the Sturt pre-selection unless they can guarantee a lavish warchest from Labor’s national head office to run a genuine “marginal-seat-style” campaign.

“Unless they’re pretty sure they can win, they don’t want to waste their bullets on Sturt,” said one insider.

Steven Marshall and Christopher Pyne on the hustings last year. Photo: AAP

Chapley, from the party’s left faction, is considered a rising Labor star. She is the in-house lawyer for her family business, which operates several Foodland stores, including in Norwood.

Sturt is now the only SA seat without a Labor candidate, after party stalwart Delia Brennan pulled out of a showdown with Steve Georganas to contest his former seat of Hindmarsh.

Nominations to contest Pyne’s seat have closed without any candidate putting their hand up, and expressions of interest are now being sought. Nominations can only be reopened by the party’s state executive, which meets on the first Monday of every month.

Pyne holds the blue-ribbon seat by more than 10 per cent on a two party-preferred basis, but yesterday’s Newspoll was grim reading for several Liberal MPs gearing up to fight for their political lives. The Coalition’s primary vote has slumped to 38 per cent, down from 45.6 at the 2013 election.

On a two-party basis, the Government trails Labor 46 to 54.

The likely presence of a slew of candidates under the Nick Xenophon banner will further complicate the contest.

Pyne, the Federal Education Minister and Leader of the House, told InDaily in a statement: “I’ve never taken my seat for granted and I won’t be in 2016.”

Labor has not held Sturt since 1972.

In May, Premier Jay Weatherill talked tough about targeting federal Liberal seats, including Sturt, arguing the incumbents had been “pathetic in standing up and fighting for South Australia”, particularly in advocating for locally-built submarines.

“Here’s how it works — we’re going to target Christopher Pyne in the next federal election and we’re going to take his seat off him,” Weatherill said at the time.

Both Weatherill and Marshall are today attending an industry briefing by a Japanese delegation spruiking their bid for the lucrative subs contract.

Marshall shrugged off any challenge in Dunstan (formerly Norwood), saying: “I increased my vote at the last election.”

“My primary vote went in excess of 50 per cent, for the first time in the seat’s history,” he told InDaily.

“You could argue we didn’t negotiate preference deals very well, but I wasn’t even reliant on preferences.”

Marshall held the seat with a 53.1 per cent two-party vote as the alternate Premier. However, that was down from his 54.8 per cent victory in 2010 as an unknown first-time candidate.

“I work extremely hard in Dunstan … I never take it for granted,” he said.

On the prospect of again facing Chapley as an opponent, he said: “It always struck me as odd that somebody running one of the largest businesses in SA would be supporting the high-taxing regime of the Labor Party.”