The federal government has offered to put up more cash for the Melbourne Metro rail tunnel, beginning towards the end of the decade, the Victorian premier says.


Premier Denis Napthine said he had received a letter from federal Infrastructure Minister Anthony Albanese offering potential funding for the rail project, on top of the $40 million already committed by the commonwealth.


The state government has allocated only $10 million in 2013/14 for the project, in comparison to almost $300 million set aside over two years for the East West Link road.


Dr Napthine said the federal government had offered funding that would flow mostly from 2019, after the first stage of the East West Link had been built.


"What that would give us is the opportunity to do stage one of East West (Link) and then look at this as a key project," he told a budget estimates hearing.


"We want this project.


"We will certainly be taking this very seriously."


Dr Napthine said Mr Albanese should match Opposition Leader Tony Abbott's $1.5 billion pledge for the $6 to $8 billion East West Link.


He said Mr Albanese had said the federal government would equalise the rules for commonwealth road and rail funding and how they impacted on the state's slice of the GST.


Treasurer Michael O'Brien said it was standard practice not to release the business case for the East West Link, as it would flag to commercial bidders how much the government was prepared to pay.


Aspiring prime minister and United Australia Party leader Clive Palmer said the East West Link should cost half of what the government had forecast.


"I've seen these figures about the link here. I had my engineer look at it, and the cost should be between $3 billion and $4 billion," he said.


Mr Palmer said in his experience in developing large projects, tenders submitted to the government were inflated.


"If someone's doing a tender for the commonwealth, they add 150 per cent," he said.


"Fifty per cent for the tax, and 100 per cent for the holiday or their retirement."


AAP