The Victorian government has been asked not to sign any more contracts for Melbourne's multibillion-dollar Suburban Rail Loop before the state election.
Opposition treasury spokesman David Davis has written to the Department of Premier and Cabinet to make the request after the coalition promised to shelve the first part of the project if it wins the poll.
"Given this commitment and the fact that the election is now just 94 days away, I write to respectfully request no further contracts be entered into by the current government into relation to this contract prior to the November 26 poll," the letter reads.
"This position is in line with the Victorian government's previous position concerning the signing of contracts close to elections, particularly in light of considerable budget and major project cost uncertainty.
"This request is made in good faith and with the best interests of the people of Victoria in mind."
The 90km orbital rail line was a 2018 election promise of the Andrews government, with work already under way on the first 26km section between Cheltenham and Box Hill.
The state's independent Parliamentary Budget Office last week revealed building the loop's first two sections would set taxpayers back $125 billion, more than double what the government previously estimated.
So far only $2.3 billion has been allocated in the state budget for early and initial works and the opposition has vowed to honour those contracts while rediverting other non-budgeted money to upgrade the state's ailing health system.
When last in government, the Victorian coalition signed a contract to construct the controversial East West Link in late September 2014, two months out from the state election.
Then-opposition leader Daniel Andrews promised to scrap the $8 billion project, declaring the contracts were "not worth the paper they're written on".
After winning that election, Mr Andrews proceeded to rip up that contract at a cost of $1.2 billion.
His government enters caretaker mode on November 1.
Mr Davis said there was "no precise date" for caretaker conventions to take effect but guidelines state they do not apply until the start of the caretaker period.
The Victorian government has been approached for comment.
