In a boost for the much-touted "missing link" proposal, the report, by economic consultants Deloitte and engineering advisers Aurecon, says the road would carry as many as 10,000 vehicles in each direction during the two-hour morning peak, while boosting the overall efficiency of the state's freight network.

As a result, Infrastructure Victoria – which commissioned the assessment – suggests the idea warrants further investigation despite the high cost. That potentially places the project on a higher footing than the ill-fated East West Link

In a major report considering hundreds of options to tackle congestion and improve efficiency released this week, Infrastructure Victoria concluded the East West Link would make a "low" contribution towards economic activity in the city, and a "low" contribution towards improving access to middle and outer metropolitan major employment centres.

It found the North East Link - which for years has been the RACV's top priority - represented a "potential alternative", concluding the benefits would be even greater if considered alongside a major new rail and road freight terminal in Melbourne's north, or a new port, particularly at Hastings.

The report follows a decision by the Andrews government to dump the East West Link after the former Napthine government signed a contract and "side-letter" locking in massive compensation just weeks before the November 2014 election.

Prime Minister Malcolm Turnbull has pinned his hopes of winning over voters in south eastern marginal electorates by continuing to back the East West Link, repeating an Abbott-era promise to hand over $3 billion to the first state government prepared to build it.

The Deloitte report said the North East Link removed significant numbers of vehicles from congested north-south roads in the inner north such as Plenty Road and St Georges Road, cutting travel time and stopping rat-runs though congested arterial roads in the north-eastern suburbs.

"Northern roads have the slowest travel speeds in the morning and evening peak periods compared to other Melbourne regions, as well as the longest delays in travel time," the consultant's report said. "North East Link is a direct orbital link from the Metropolitan Ring Road to EastLink."

"The new Link will relieve existing Yarra River crossings and it may also encourage east-west cross regional movements via the Metropolitan Ring Road. By 2031, the North-East Link is forecast to carry 10,000 vehicles in both directions during a two-hour peak period ..."

The report, which has been publicly released by Infrastructure Victoria, also suggested the link would improve freight productivity by connecting freight centres around Dandenong with the Hume Highway and farming areas in the south-east.

"The North East link will improve access between the potential Beveridge Interstate Rail Terminal and industrial areas in Bayswater, Clayton and Dandenong and between the Melbourne Wholesale Fruit and Vegetable and Flower Market and the productive food areas of the South East of Victoria," the report said.

Late last month State Treasurer Tim Pallas said he believed the project "innately" made sense. "If you look at the way that most modern cities operate, this idea of an outer suburban high capacity freeway network I think has a lot of merit to it," he said.

Several options for the road are believed to be under consideration, including a link from the Eastern Freeway at Bulleen through Banyule to Greensborough and the Ring Road, or the road from EastLink at Ringwood around Eltham and connect to Greensborough through a slightly longer route.

Labor strategists believe the proposal would answer critics' claims that motorists in parts of Melbourne have been badly let down following a decision to cancel the East West Link contract.

Opposition leader Matthew Guy has also signalled plans to offer up the road proposal as part of the Coalition's 2018 election pitch, recently claiming it was "utterly overdue".

"Closer to the election I can give you an absolute guarantee you will see some … announcements from the Coalition around road infrastructure in Melbourne and it will feature the North East Link and it will feature the East West Link," he said.

Infrastructure Victoria chief executive Michel Masson stressed that the hundreds of ideas being examined were "options not recommendations".

"There is no silver bullet, and no one solution," he said. "We are also not solely focused on building new infrastructure. We are looking for ways to better manage demand and better utilise existing assets before we building new things."