The fight to replace Alan Tudge in the Aston by-election is shaping up as a Melbourne Cup field of candidates.
Labor has announced breast-cancer survivor Mary Doyle will aim to put health care on the national agenda in her bid to win the Victorian seat being vacated by the retiring federal Liberal MP.
Mr Tudge on Friday delivered his resignation letter to Speaker Milton Dick, who is considering a date for the by-election, which is expected to feature candidates from the major parties, Greens and One Nation and possibly an independent.
Ms Doyle was selected by Labor to take a second shot at the seat, having won 47.2 per cent of the two-party vote in 2022.
Raised in Echuca, the former union official was diagnosed with breast cancer in her mid-20s and is a single mother of two children and carer for a third.
She said she was a suburban parent, not a seasoned politician.
"I know it's tough out here for the people in the outer eastern suburbs," she told reporters while announcing her candidacy on Friday.
"I promise to work every single day to make sure the voices of people are heard loud and clear."
Prime Minister Anthony Albanese said Ms Doyle was a strong candidate, even though the odds were against her.
"She doesn't want to do this for herself. She wants to do this for her kids as a single mum. She wants to do this for the people of Aston," he said.
Mr Albanese acknowledged it would be difficult for Labor to win the seat because a sitting government hadn't won a by-election in more than 100 years.
He said the Liberal Party would be the favourites "if they get around to selecting a candidate".
Senior Liberals are pushing for a strong, local female candidate, but a final decision has not been made.
Former Victorian upper house MP Cathrine Burnett-Wake announced on Monday she would nominate for the Liberals.
The former Yarra Ranges councillor said she had been encouraged to run by Aston community members and spruiked her connection to the electorate, including her children attending a local school in Wantirna South.
Another potential candidate is Melbourne City councillor Roshena Campbell.
Opposition Leader Peter Dutton said the Liberals would choose a strong, local candidate.
"The prime minister's got an advantage in his party where he can just appoint candidates and go straight over the top of the wishes of local candidates, local members and not listen to the will of their local membership," he said in Melbourne.
"In our party, we're much more democratic in that sense and that's a good feature of our party, but we'll select a strong candidate, we want somebody who understands the issues here in Aston."
There is potential for an independent candidate in the by-election and Climate 200 convenor Simon Holmes a Court has signalled his support for such a move.
"If there's a community group in Aston planning to run a pro-climate independent campaign, we'd love to hear from them," he told AAP.
"This is how we've always operated - we never start a campaign or get involved in community selection processes, but we're here to ensure good, community-based independents have a fighting chance against the party machines."
One Nation will run a candidate, following discussions at the party's national executive.
The Greens are also likely to select a candidate, with climate change policy expected to be a key issue.
Clive Palmer's United Australia Party is yet to make a decision, having run a candidate in 2022.
