South Australian Liberal MP Nicolle Flint has refused to answer questions about whether she regrets supporting the call for a leadership spill that ousted former prime minister Malcolm Turnbull.

Key points: Incumbent Boothby MP Nicole Flint supported a spill against former PM Malcolm Turnbull

Incumbent Boothby MP Nicole Flint supported a spill against former PM Malcolm Turnbull The Liberals hold the seat of Boothby with a 2.7 per cent margin

The Liberals hold the seat of Boothby with a 2.7 per cent margin Labor candidate Nadia Clancy said Boothby voters were "sick of politicians"

The Boothby MP was one of 43 Liberal MPs who signed a petition calling on then prime minister Malcolm Turnbull to call a meeting to determine "the leadership of the party" in August last year.

During a debate on ABC Radio Adelaide with Labor candidate Nadia Clancy, Ms Flint was asked by her opponent why she supported the call for the spill, which led to the fall of Mr Turnbull and the elevation of Scott Morrison as Prime Minister.

Ms Flint urged people not to focus on the past during the upcoming election.

"We can focus on the past at this election — I know your GetUp! and union mates would like to distract people with this question — but we have a clear choice during the upcoming election," Ms Flint said.

"A choice between Prime Minister Scott Morrison, with lower taxes, plans for a stronger economy and guaranteeing of central services, or it's a choice of a Bill Shorten government, who will devastate our retirees."

ABC Radio Adelaide co-presenter Ali Clarke interjected and asked: "Nicolle Flint, do you regret your role in this?"

The question was repeated, before Ms Flint restated her desire for Boothby voters not to "dwell on the past".

"I'm asking voters to look at my very strong record of delivery for our community," she stated.

She said she was "not asking people to forget" but to focus on the "very clear choice at this election".

Co-presenter David Bevan replied: "Yes or no, do you regret your decision in deposing Malcolm Turnbull?"

"Scott Morrison is the Prime Minister, David, and I'm saying to people they've got a very clear choice at this election," she replied.

The seat of Boothby, which covers suburbs south of Adelaide and part of the coast, is South Australia's most marginal seat, with a 2.7 per cent margin following the 2018 redistribution.

People are 'sick of politicians'

During the debate, Ms Clancy admitted that people were "sick of politicians" on both sides of politics and it was time to throw scare campaigns and misleading language out the window.

Ms Flint asked Ms Clancy: "Why do you, your leader Bill Shorten and the Labor Party want to hurt local retirees, small businesses, mum and dad investors in Boothby with taxes on their homes, investments and on their savings?"

Ms Clancy responded that she was out doorknocking "regularly", speaking with people and making phone calls and the message was clear.

"People are just done with this kind of language and done with people being misleading … people are over it," she said.

When it was pointed out to Ms Clancy that Labor "wrote the book on scare campaigns" with the 'Mediscare' campaign three years ago, she was asked if her party could really take the moral high ground on this issue.

She replied that Labor had been clear "this election" that it wanted to put an end to scare campaigns and be a "positive party".

David Bevan asked what was the difference between Ms Flint asking people to forget her role in the leadership spill and Ms Clancy asking people to forget Labor's past scare campaigns.

"You say people are sick of this sort of thing, maybe they're sick of both of you?" he asked.

Ms Clancy agreed and said "honestly, people are sick of politicians in general".

"I sit down with people and have a long conversation and chat with them and I understand the initial response is, 'Oh God, can you get a politician or a potential politician out of my face because I'm over this and I just want people to listen to me and represent me'."

The issue of franking credits a hot topic

The Labor candidate was also asked about her party's proposed changes to franking credits — a taxable rebate to shareholders who receive dividends which have already incurred company tax.

The Howard government introduced paying out franking credits to shareholders who did not have enough tax to offset. ( AAP: Tracey Nearmy, file photo )

"We will still be giving people franking credits where they can reduce their tax bill to zero," she said.

"No-one on a pension or part-pension will be affected by our policy.

"What we're doing is stopping tax refunds to people who haven't paid tax — a policy that is currently costing our budget $6 billion a year and is forecast to cost $8 billion a year in the future and we need to be putting those billions of dollars into our healthcare system."

She said she did not have a figure of how many Boothby residents would lose income under the proposed changes, however, Ms Flint said people would be losing between $5 and $15,000.

"These are not wealthy people — these are people who have worked incredible hard to provide for their own retirement," she said.

"People who are proud of the fact that they are supporting themselves so they're not having to take money from Australian taxpayers. They don't want to be a burden on the system."

Ms Flint asked her competitor whether a Labor government would also commit to fixing the Hove level crossing on Brighton Road, the intersection at Fullarton Road and Cross Road and reactivate the Repat Hospital.

She said that it would match all commitments.