Barrister and Melbourne City councillor Roshena Campbell has been chosen as the Liberal Party candidate for the marginal seat, following a senior leadership meeting.
Mr Dutton said he had voted for Ms Campbell as she would be a fierce local member and had the respect of the party and the community.
He claimed Labor had cut funding to the electorate's key infrastructure projects in the October budget and had not taken steps to ease cost of living pressures.
"The prime minister has to explain why in their first budget, when they had the first opportunity to demonstrate commitment to Aston, did they cut these projects and spend the money elsewhere," he said.
"The community wants a fighter and in Roshena they'll get somebody who will stand with them and fight for them on local issues."
Ms Campbell said she wasn't taking the seat for granted and promised to move to the Aston electorate before the by-election.
"I'm going to take the time to visit every inch of the seat, I'm going to be doorknocking and make sure that I am a champion for voters," she said.
"Cost of living is hitting hard with 41 per cent of people here having mortgages, a number of young families and a number of people coming off fixed interest rates."
Ms Campbell said if elected she would push the Labor government on plans to address spiralling inflation.
Mr Dutton blamed the short timeline to the April 1 by-election as the reason why the party couldn't hold a full ballot with all branch members.
"I've always been in favour of the democratic processes in our party ... our timelines were set by the government when they made an announcement to hold a by-election before the May budget," he told reporters in Melbourne.
"It's clear the fact that they've rushed the by-election, they want to get it over and done with before the budget."
The Liberals' margin in Aston was cut from 10.1 per cent to 2.8 per cent at the May 2022 election.
Last week, Labor announced former unionist and finance worker Mary Doyle, who ran against Mr Tudge in the 2022 election, would be their candidate in the by-election.
