The Coalition is investigating the possibility of combining the North East Link road project with a rebooted East West Link if elected at the end of 2018. But Mr Guy emphasised that the controversial $5.8 billion East West Link - which was spiked by the Andrews government at a cost of more than $1 billion - was his party's priority.

Powerful roads group the RACV said the North East Link was needed before the East West Link, and public policy manager Bryce Prosser warned of traffic chaos if roadworks shut down too many existing routes at once.

"There will massive disruption to the residents in the north and the north-east getting to and from the city for a long period," Mr Prosser said.

Infrastructure Victoria, the government's advisor on major infrastructure projects, has also named the North East Link as a priority project in its 30-year strategy. It said the East West Link would not be needed for up to 30 years.

Labor will soon announce the route of its proposed North East Link, to cost around $10 billion.

It will fill the "missing link" in the Melbourne's ring road, connecting the M80 at Greensborough to either the Eastern Freeway or EastLink.

The cheapest and preferred route will run through Mr Guy's electorate - Bulleen - triggering local fears that homes, school and sporting facilities will be demolished.

Mr Guy said he supported the North East Link, but it was "crazy" to build a tollway that would funnel 100,000 extra vehicles onto the Eastern Freeway, with the road predicted to carry this number of cars each day if the Bulleen road is chosen.

"The East West Link must be constructed before any North East Link option," he wrote in a letter to Bulleen residents. "We're looking at how we might be able to either package up the projects or indeed go as individual projects."

It is entirely possible to build both tollways at once, says Terry Rawnsley from SGS Economics and Planning, who has advised the government on both the East West Link and the Metro Tunnel projects.

"Whether it's sensible in the short term is the bigger question," he said. "There is a degree of competition between two links ... you don't want to over-invest in infrastructure."

The possibility of the two multi-billion dollar projects going ahead alongside Transurban's West Gate Tunnel project would usher in the biggest phase of road construction the state has seen.

The North East and East West projects have been debated for almost half a century, since they were first proposed in a state transport plan back in 1969.

"But that does not mean that these projects are good ideas," warns Melbourne University planning academic Dr Crystal Legacy.

A road-building boom on this scale would see Victorians "locked into a future structured around car dependency," she said.

Premier Daniel Andrews said he would be backing the North East Link at the election next year.

"We won't be putting in poison pill side letters like the previous government did," the Premier said.

"While they talk about building projects, we get on and build them."

With Adam Carey