More than $2 billion in funding for Melbourne's Suburban Rail Loop may not be rerouted to health by the federal government if state opposition wins the upcoming election.
Before the May national poll, Prime Minister Anthony Albanese announced an initial $2.2 billion federal commitment towards funding the 90-kilometre orbital rail line running from Cheltenham to Werribee via Melbourne Airport.
The Victorian coalition has since promised to shelve construction of the line's first stage, worth up to $34.5 billion, to prioritise funds for the state's ailing health system if it wins the November state election.
But Mr Albanese has declared the federal money cannot be spent elsewhere.
"The Commonwealth determines where our investment goes. We ... make commitments based on our priorities," he told the Herald Sun.
"We have provided significant health funding for Victoria and we'll do that into the future. It's not either or."
AAP has contacted the prime minister's office for comment.
In response, the Victorian opposition plans to write to Mr Albanese to plead its case for the money to be rerouted to health.
Shadow treasurer David Davis insists the letter is not a waste of time despite Mr Albanese's public comments.
"I believe he will respond to sensible points," he told reporters at state parliament on Tuesday.
"He will respond to the will of the Victorian people if the Victorian people at the election make a clear decision that they actually want the money reprioritised."
Mr Davis insisted the circumstances were different to those from 2015, when former prime minister Tony Abbott maintained a so-called "locked box" of federal funds to build the controversial East West Link despite the project being canned by the Andrews government.
"There has been independent assessments here. It's clear the project doesn't stack up, and it's clear that we have a more urgent crisis in the state," Mr Davis said.
Victoria's independent Parliamentary Budget Office this month released a report that found building the first two sections of the rail loop could set taxpayers back $125 billion, more than double the previous estimate.
It also calculated the cost-benefit ratio for those sections at between 0.6 and 0.7 - meaning the state would reap between 60 to 70 cents for every dollar spent - lower than a previous estimate of 1 to 1.7.
