Prime Minister Scott Morrison is promising to spend $4 billion on Melbourne's shelved East West Link road project, even though the state Labor Government has ruled out its construction.

Key points: A Coalition government would fund a road tunnel connecting the Eastern Freeway to Citylink

A Coalition government would fund a road tunnel connecting the Eastern Freeway to Citylink Premier Daniel Andrews cast doubt on the project, calling the funding promise a "con"

Premier Daniel Andrews cast doubt on the project, calling the funding promise a "con" Federal Labor has backed Mr Andrews' Suburban Rail Loop plan with a $10 billion funding promise

In a sign of how critical Victoria could be to the election result — and the popularity of infrastructure projects in the rapidly growing state — Opposition Leader Bill Shorten has also made a pitch to local voters, with a $10 billion commitment to Premier Daniel Andrews's suburban rail loop.

Mr Andrews promised at the last state election to build a 90-kilometre train line from Cheltenham, in the city's south-east, around outer Melbourne via the airport to Werribee, in the outer west.

It would include 12 new underground stations.

The project is estimated to cost more than $50 billion and take decades to build.

A map showing the route of the Victorian Government's proposed suburban rail loop. ( ABC News )

Mr Shorten's commitment is the latest in a series of pledges to work with the Andrews Government on major projects, including $2 billion for Melbourne's Metro Tunnel project.

Morrison 'can get the city moving'

The Coalition made its East West Link promise while launching its re-election campaign in Melbourne today.

Mr Morrison's $4 billion pledge would go towards a road tunnel between the Eastern Freeway and Citylink in Parkville. It is likely to be popular with some voters in Melbourne's east.

Reviving the East West Link is aimed particularly at voters in Liberal-held eastern suburbs seats including Deakin, Chisholm and Kooyong.

Mr Morrison said the project was "about standing by eastern Melburnians who want to get out of the gridlock so they can spend more time with their families and so they can get to work without wasting hours each week on the road".

The Andrews Government, which would have to sign off on the project, is refusing to build it.

"I accept that the Victorian Government has not identified the East West Link as a priority for them," Mr Morrison told today's campaign launch.

"So just let us get on and do it."

'Last-minute con'

When first proposed, the East West Link project attracted significant opposition from residents in suburbs such as Clifton Hill and Collingwood, where dozens of homeowners faced losing their properties.

But a revised plan put forward by the state's then-opposition leader Matthew Guy last year would see the entrance moved to the median strip of the Eastern Freeway.

The tunnel entrance for the East West Link would be built on the median strip of the Eastern Freeway under a Coalition proposal. ( ABC News )

Labor campaigned at last year's state election on instead building the North East Link, connecting the Eastern Freeway and the M80 Ring Road at Greensborough, and the Suburban Rail Loop.

Mr Andrews cast doubt on whether the state would ever see the "paltry amount" of money offered by Mr Morrison for the East West Link.

"This is the most desperate last-minute con that I think I have ever seen," he said.

Shorten pledges record rail cash

Mr Shorten also began the day in Melbourne with a promise for the single biggest federal investment in a public transport project in history, with a $15 billion, 15-year investment.

That includes $5 billion towards the Airport Rail Link, which the Coalition had already allocated.

Mr Shorten said the Suburban Rail Loop, which work will not start on before 2022, would be a "game-changer for Melbourne and Victoria".

"It will stretch right around our city," he said.

"We will finally defeat the proposition that to get anywhere else in Melbourne, you have to go into the middle."