Vic Labor silent on full rail loop cost

Victorian voters are set to head to the polls without an updated cost estimate on building Labor's entire signature Suburban Rail Loop.

The coalition, which has vowed to shelve the project if elected, has accused Labor of breaking a promise to provide full up-to-date figures before Saturday's election.

The 90km orbital rail line was a 2018 election promise of the Andrews government, with early works already underway on the first 26km eastern section between Cheltenham and Box Hill.

In 2018, the government said the entire project would cost up to $50 billion to build.

But the state's independent Parliamentary Budget Office in August found constructing the loop's first two sections would set taxpayers back $125b.

That is more than double the previous estimate of up to $50.5b given in a Labor-commissioned 400-page business and investment case released last year.

Independent agencies Infrastructure Australia and Infrastructure Victoria have not assessed the project, with the latter not recommending a suburban rail loop in the state's first 30-year infrastructure strategy in 2016.

After the budget office crunched the numbers, Mr Andrews was quizzed on whether Labor would provide a new estimate on the full cost of the project before the election.

"Sure, that's absolutely fine," he told reporters in mid-August, adding he was happy to have Ms Allan come back with the most up-to-date version.

Peppered with questions on the rail loop for more than 25 minutes on Wednesday, Mr Andrews reiterated the east section's projected cost of $35 billion but declined to provide a current estimate for subsequent stages.

"The subsequent stages of this will be for governments in the very late 2030s, 2040s and the 2050s," he said. 

"The scope and scale and modelling and conditions and circumstances ... they'll be relevant then, but that will be a matter for future governments. 

"That's the nature of multi-generational investments."

Liberal Leader Matthew Guy said it amounted to a broken promise.

"The government said they'll release the figures, they haven't. It's straightforward," he said at Merinda Park Station.

Budget constraints mean the coalition would be unlikely to restart construction on the loop's east section in its first term if elected, Mr Guy said.

But the coalition this week pledged to begin planning on a second underground metro rail link in Melbourne, dubbed Metro 2.

Metro 2 has been backed by Infrastructure Victoria and previously costed at between $12b and $20b.

In the Labor-held seat of Cranbourne, Mr Guy announced the coalition would bring forward its $2 flat daily fare for public transport in metropolitan Melbourne and half-price V/Line fares by six months to January 1, if elected.

The PBO has calculated an extra six months of the policies, which were previously slated to start in the 2022/23 financial year, at $140m.

Mr Guy said Victoria's net debt levels would be significantly lower over forward estimates under a coalition government than Labor, with the figure for June 2026 forecast at $165.9b in the pre-election budget update.

But voters will have to wait until Thursday to find out by how much, when the Liberal-Nationals release their full policy costings.