A deal to get the wheels turning on a rail line to Melbourne Airport may not be brokered before the next Victorian election, the transport infrastructure minister admits.
The airport and state government remain locked in a stalemate over whether a station at Tullamarine should be underground or elevated as part of the Melbourne Airport rail project.
With construction halted and an independent mediator appointed, the project's completion date has been pushed back at least four years until 2033.
Deputy Premier Ben Carroll raised hopes of a potential compromise, suggesting the state government could be willing to bend on building the station underground if it was fully funded by the airport.
Mr Carroll, whose electorate of Niddrie stands to benefit from the planned rail line, doubled down on his stance on Tuesday.
But Transport Infrastructure Minister Danny Pearson quickly tempered expectations when asked if the government would get a deal done before the 2026 state election.
"No, I can't guarantee that," he told reporters at state parliament.
"I can't guarantee that because we are dealing with a rapacious private operator that has shown no interest to date in doing a deal."
In 2018, the Victorian and federal governments committed to contributing $5 billion each to the project, expected to cost between $8 billion and $13 billion.
Melbourne Airport was part of a consortium the following year that offered up to $7 billion towards an underground airport station and express tracks from Sunshine to Southern Cross.
Mr Pearson said the deal was a "sham" and flatly rejected by the then-coalition federal government and the state.
"It would have locked in super high rates for the travelling public of Geelong," he said.
"It was a dud deal - it stank to high heaven."
Melbourne Airport's land is leased by the Commonwealth to the Australia Pacific Airports Corporation Limited under a 50-year deal.
It means any planning application for the Commonwealth-owned land must be submitted by the airport.
"We can't get this deal done unless the airport give consent," Mr Pearson said.
The minister met with the airport's chief executive Lorie Argus in December and Mr Pearson said he was willing to sit down again.
He confirmed state government officials have met with the Commonwealth-appointed mediator, former Queensland transport department director-general Neil Scales.
A Melbourne Airport spokesman said it had held "positive discussions" with the mediator and remained fully engaged in the process.
"Melbourne Airport remains available to discuss potential funding opportunities for an underground station," he said in a statement on Monday.
Opposition Leader John Pesutto suggested Mr Pearson and Premier Jacinta Allan were "at odds" with Mr Carroll on how to progress the project.
"He's trying to find a solution," he said.
"But it seems that the Premier Jacinta Allan and infrastructure minister Danny Pearson are the ones standing in the way."
The airport rail back-and-forth came as the government confirmed it had indefinitely deferred the delivery of an interstate freight terminal in Melbourne's west, sparking fears of more trucks crowding roads.