Environment and Sustainable Development Minister Simon Corbell will announce the plan on Saturday, the same day the government releases a report showing a cost benefit analysis of the $614 million city to Gungahlin project.

The report, lodged with Infrastructure Australia last year, shows an economic benefit of $2.34 for every dollar spent on light rail, if the network leads to increased development in the 12.5-kilometre corridor.

But the report warns the project could result in "negative economic returns" if light rail does not lift the rate of development through the Civic to Gungahlin stretch.

The government will lodge a new submission with Infrastructure Australia for $15 million, which it will use to fund further analysis to determine the economic effects of the project.

The move comes after Infrastructure Australia identified a need for more work to show how the project could lift development along the transit corridor above what is already expected through population growth in the ACT.

Light rail did not make a national infrastructure priority list published by Infrastructure Australia earlier this month. But the government made its 2012 submission to the agency before reaching its decision to proceed with light rail and not the bus rapid transit along the corridor.

The submission, to be published on Saturday after demands by the ACT opposition, shows that light rail, under a "higher density scenario", would deliver an economic benefit of $2.34 for every dollar spent.

The scenario assumes that light rail would increase population levels in the corridor by 380 per cent and employment levels by 21 per cent.

Under a "business as usual" scenario based on current ACT population and employment projections, the network would deliver $1.02 for every dollar spent, with the risk that the outcome "under even minor adverse circumstances is likely to result in negative economic returns".

But Mr Corbell said that the higher density scenario was more likely "because that has been the experience of light rail in every other city in the world". "The provision of a permanent rail transit corridor leads to a higher level of investment activity because it is a more attractive place for people to live and work and because of the convenience of rail."

Mr Corbell said the report showed the return from light rail was particularly favourable for the ACT compared to other cities that were building light rail networks.

"The Gold Coast light rail, for example, has a benefit cost ratio of 1.65," he said. In NSW, the O'Farrell government is pursuing light rail in Sydney's inner west with a benefit cost ratio of 1.

Mr Corbell said Infrastructure Australia looked closely at projects with a benefit per dollar spent of at least 2. He said the new bid for funding would also make a stronger argument for the national significance of the capital metro network.

"Our message, in part, will be this is the front door of the national capital," he said. "Northbourne Avenue is the front door of the national capital and it deserves to have engagement on the part of the Commonwealth as well as on the part of the territory to make it an entry worthy of our national capital."

Mr Corbell said that while the government was seeking funding for further economic analysis, this would be done in tandem with design work for the project. Construction would still begin by 2016.