Vic debt only for infrastructure: Pallas

Victoria could take on billions of dollars of new debt to fund its infrastructure projects, Treasurer Tim Pallas says.

After putting out a hand for federal funding for the $10.9 billion Melbourne Metro Rail project, Mr Pallas gave a "rock hard guarantee" Victoria would only use debt for important infrastructure.

"Once I've got rock hard, I'm staying rock hard for the purposes of commitments that I give," Mr Pallas told reporters on Friday.

"That we will absolutely ensure that we will only use those borrowings for the purposes of building economy-growing infrastructure.

"Economic infrastructure, whether it's Melbourne Metro, whether it's roads in our rural and regional areas, whether it's our water networks, all of these things."

Mr Pallas said Victoria was one of the few triple-A rated economies in the world, and could borrow at very cheap rates.

The Victorian budget is due in May.