Prime Minister Anthony Albanese has positioned Labor as the underdog, constantly referring to the fact a governing party hasn't won a seat off the opposition at a by-election in over 100 years.
He said anything less than a "massive" majority for the Liberals would be an indictment on Mr Dutton's leadership, adding that the close contest "says everything about the state of the Liberal Party brand".
After the NSW state election, the Liberals no longer hold government at federal, state or territory level anywhere on the Australian mainland.
Aston is held by the Liberals on a slim 2.8 per cent margin after former minister and outgoing member Alan Tudge suffered a large swing against him at the 2022 poll.
Labor candidate Mary Doyle said the Albanese government was making a difference for households doing it tough due to the rising cost of living.
Ms Doyle is a breast cancer survivor and former unionist who failed to take the seat at the last election.
"Everywhere I go in the electorate, people - regardless of where they come from - are raising cost-of-living pressures with me," she told AAP.
"But people also say they are seeing the Albanese government making a difference for households in managing their budgets through cheaper child care and cutting the cost of prescription medication."
Mr Dutton says the Liberals should be able to retain the seat but has played down the expectation of a massive swing away from the government.
"I think we will get there, but it is a tight race as by-elections always are," he said.
The Liberals are also focusing on the increasing cost of living, which is being driven by inflation and interest rate hikes.
"Every decision Labor has taken economically over the course of the last 10 months has driven up the cost-of-living pressures on families and on small businesses," Mr Dutton said.
Former Melbourne City councillor and barrister Roshena Campbell is fighting to keep the seat for the Liberals.
She says the government has abandoned people in eastern Melbourne after ripping out funding for local roads and rail.
Other candidates for the seat are project manager Angelica Di Camillo (Greens), software engineer Owen Miller (Fusion) and libertarian advocate Maya Tesa (independent).
Just over 110,000 people are enrolled to vote in Aston and ballots can be cast at 32 polling places, which are open from 8am to 6pm.
Electoral commission figures released on Friday showed 23,298 people had cast an early vote, compared with 35,055 at the same time before the 2022 election.
Almost 18,000 postal vote applications have been received and voters have until 13 days after Saturday to get their postal ballots back to the AEC to be included in the count.
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