Melbourne's CBD will face significant disruption for years once digging on the $10 billion Melbourne Metro Rail tunnel begins down Swanston St.

The major tram thoroughfare through Melbourne has been chosen as the preferred route for the tunnel, which will be just 10 metres below street level.  Premier Daniel Andrews promised an open consultation with traders and a fair compensation process for anyone affected by the tunnelling work.

“You won’t see the whole street closed at once, it’ll be done in a staged way,” Mr Andrews told reporters

“We’re not gilding this. There will be disruption, and we apologise in advance for the progress we’re going to make.”

Transport Minister Jacinta Allan said a “cut-and-cover” method would be used at each end of Swanston St, while a tunnelling machine worked underneath the street.

The Metro Rail tunnel was first proposed under Labor in 2009 but shelved by the previous coalition government in favour of a direct route and an airport rail link.

The original funding plan called for a third of the money to come from the federal government, but Mr Andrews said the state was prepared to go it alone.

“The current federal government have made it clear they will not be a partner in this, and I see no purpose frankly in continuing that argument with the current federal government,” he said.

Mr Andrews said the private sector would still be involved in funding the project.  The twin 9km tunnels will sit above the city loop rail tunnel, and above the CityLink road tunnel, before diving underneath the Yarra River.

The project includes five new stations, including one at the Domain, one in the Parkville hospital precinct, and two underground stations connecting the tunnel to the city loop.

Mr Andrews said construction would begin before the end of 2018.

Expressions of interest in the project will go out in 2016.

Mr Andrews said the tunnel was an “oak tree” project that would take many years to deliver.Metro

“Perhaps the people who start it won’t necessarily be there at the end to see it finished,” he said.

Mr Andrews said the final business case would be released once it was completed, but it would have a positive cost-benefit ratio.