The Mayo by-election race has heated up, with the Prime Minister hitting the hustings alongside Liberal candidate Georgina Downer today to announce funding for an aquatic centre rebuild at Mount Barker in the Adelaide Hills.

The $10 million grant is the first major commitment of the campaign, and will go towards the $25 million cost of replacing the current open-air Mountain Pool, which was built in 1955.

Prime Minister Malcolm Turnbull, who announced the funding with Ms Downer in Mount Barker today, rejected suggestions the Liberal candidate was out of touch with locals.

"I haven't met anyone today who doesn't know her," the Mr Turnbull said.

"Her roots are in this electorate, in this community. You can see the passion she has for it.

"Georgina is presenting herself as an advocate, as a powerful advocate, but one who can work within the Government."

Ms Downer is the daughter of long-time Mayo MP Alexander Downer, but has recently been based in Victoria and unsuccessfully sought pre-selection for the Melbourne seat of Goldstein in 2016.

The aquatic centre project will include three indoor swimming pools, a community recreation space and an indoor multi-purpose stadium. Land has also been set aside for an outdoor pool to be built in the future.

The Mountain Pool in Mount Barker was built in 1955. ( Facebook: Mount Barker Mountain Pool )

Centre Alliance candidate Rebekha Sharkie welcomed the funding as a "great win" for the local community.

But she added that she helped lodge the application for the project earlier this year, before she resigned from Parliament because of her citizenship.

"That's why I was surprised to hear the Prime Minister wasn't aware of the project, because we certainly put it in several months ago," she said.

"I'm really pleased that [the] Government's funding this, I think that's terrific. But let's not forget why they're funding this — they're funding this because we are a marginal seat.

"The Prime Minister wouldn't be here today if this seat was held by a Liberal."

The Government said the new aquatic centre would deliver more than 60 direct and indirect jobs while construction is underway, with 30 direct and indirect ongoing jobs once the pool is open.

Mayo voters will head to the polls on July 28, along with those in four other electorates around the country.

Downer questioned about foreign policy

Last night, Mr Turnbull and Ms Downer met with locals at the Alma Hotel in Willunga south of Adelaide for a so-called "politics in the pub" question and answer session.

The pair enjoyed pints of beer with locals, but faced sustained questioning over coal mining, energy security and social policy, among other issues.

Georgina Downer and Malcolm Turnbull with locals at the Alma Hotel in Willunga. ( Facebook: Georgina Downer )

Mr Turnbull defended the Government's position on the live export trade, and his resistance to a ban.

"Phasing out exports would mean phasing out Australian jobs," he said.

Local resident Doug asked Ms Downer, who is a former diplomat and self-described "foreign policy expert", about the decision to invade Iraq in 2003, when her father was Foreign Affairs Minister.

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"What would you have done differently?" he asked.

But Ms Downer would not be drawn, referring to the war in Iraq as a "historical" issue.

"Do you know what I'm really focused on at the moment? I'm really focused on listening to locals in Mayo tell me what they're concerned about," she said.

"You're asking me a question about which I had no involvement.

"It's a historical question that doesn't really add, I don't think, to the debate of what matters to people in Mayo going forward."

Most of the detailed estimates of the Iraq war death toll put the figure at beyond 100,000.