The "Intercity" report calls for the introduction of new regional trains able to travel at 200 kilometres per hour, and rail upgrades that would allow this high-speed operation "where achievable".

The Melbourne to Geelong train trip would be cut from an hour to 35 minutes and a new "fast line" would link the CBD with the airport.

A revamped regional rail network would help ease the burden on Melbourne from its massive population growth, by encouraging more Victorians to live in regional cities, it says.

The plan, prepared by the Rail Futures Institute and to be launched on Monday by former deputy prime minister Tim Fischer, says a better regional rail network would allow thousands more country residents to commute to Melbourne for work, while enabling more Melburnians to travel to jobs in regional cities. It says Victoria should aim for a regional population of at least three million by mid-century.

Key priorities listed in the report include:

• A new fast line to Geelong.
• Linking of Geelong, Ballarat and Bendigo via a new standard gauge rail network.
• Line speed upgrades with improved signalling and level crossing protection.
• Upgraded country railway stations.
• Quadruplication of the Caulfield-Dandenong line, considered crucial for better regional services.
• Additional tracks on parts of the Gippsland and Ballarat lines shared with metropolitan trains.

The report calls for a Melbourne Airport link to be built by 2030 to high-speed-rail standards. It would deliver a Southern Cross to Airport journey time of 15 minutes. Beyond the airport, new lines would extend to the Bendigo and Seymour routes.

"The route from Southern Cross Station would be partially in tunnel and partially on the surface or elevated, with line speeds of 160 to 200 km/h," the report says.

"It is essential that detailed planning commences as soon as possible, to determine and safeguard its final alignment," it says.

Faster trains combined with higher specification tracks would cut journey times on the wider regional network, the report says. The Melbourne to Gippsland service would become at least 30 minutes faster, for instance.

While the report says the state's regional rail system needs major investment, it also acknowledges that it is both popular and a key building block.

"Victoria has a strong rail foundation on which to build a new regional network to support growth. This rail legacy would cost billions of dollars to build today. It is an invaluable asset," the report says.

It also says: "V/Line patronage has more than doubled in the last decade. Key factors include population growth, rising costs and congestion that discourage car travel, and new service provision under various investment programs. Rail demand is projected to continue to grow, but significant capacity gaps will limit the ability to provide additional services. Expansion of regional rail is severely hampered by a legacy of under-investment in Melbourne metropolitan rail infrastructure."

The secretary of the Rail Futures Institute, Bill Russell, said he believed the plan was  "the most comprehensive plan for the rail system and for linking it to state and regional development that's ever been produced".

A revamped regional rail network could "help distribute economic and social benefits across the state," he said.

"Melbourne is already experiencing the difficulties of rapid growth, urban sprawl and traffic congestion choking the city.  Building more roads will not solve the problem," he said.