Funded from the sale of assets including ageing public housing stock and out dated government office blocks, the Capital Metro payment will also include money raised from the 15 per cent "asset recycling" bonus from the Abbott government, worth $60 million and announced earlier this year.

For planning purposes, the budget papers fund the cost of the 12-kilometre tramline as if it was being built wholly by government, despite being planned as a public-private partnership.

The $375 million contribution payment, calculated as half of a roughly $750 million total project cost, will only be paid after completion of construction and the start of services on the line from the city to Gungahlin, expected in 2019.

The full cost – expected to be about $783 million – will be paid through a combination of the capital contribution and availability payments made over 20 years. Officials said the $375 million capital contribution, which falls outside the current budget cycle, meant the project remained commercially attractive.

The government is yet to make a decision on the possible extension to Russell for the line. An "extension option paper" will be provided by each of the two shortlisted consortiums bidding for the project this year, before contracts are signed in 2016.

Public transport attracts about 3 per cent of the budget's funds, or $152.4 million.

The figure is about $394 for each ACT resident.

ACTION buses will receive an extra $17.2 million this financial year to deal with operational capacity and worker's compensation costs, after a review found significant cost pressures. It will consider long-term funding of the network after improved business practices are implemented.

ACTION fell short of its patronage projections, recording 17.8 million boardings rather than 18.5 million budgeted.

It also fell short of targets for services operating on time: 73 per cent of buses turned up on schedule. The target was 75 per cent for buses arriving one minute before timetabled or within four minutes after.

The network cost per passenger boarding was $7.90, more than 40 cents above the government target.

The flexible bus service for older Canberrans will receive $496,000 to continue operation and $264,000 will go this year and next to the Nightrider bus service from the city to the suburbs late at night.

As part of its ongoing efforts for transport reform, the government will spend $690,000 to conduct a targeted road corridor efficiency trial to improve traffic flow on congested roads and a whole-of-government peak oil strategy will be developed.

Chief Minister Andrew Barr said he had "reached across the aisle" to join the federal government asset recycling scheme.

"It was approipriate in this budge to demonstrate our progress," he said.

"As we move through the rest of the asset recycling scheme you will see that provision build, noting of course that our decision here is to make a capital contribution once the construction of the project is complete."