Almost $52 million will be allocated in next month's ACT budget to construct a light rail system in Canberra.

The money will be spent over the next four years, progressing the first stage of Canberra's light rail network from Gungahlin to the city.

The Capital Metro Minister Simon Corbell said it would be used during the design and construction phase.

"This funding will provide for the provision of specialised technical, program management, legal and commercial advisory services," he said.

He said the next 12 to 18 months were critical for the light rail project.

"We need to finance that important work, in particular the legal, technical and other specialist advice we need to deliver Canberra's first light rail line for our city," he said.

The successful bidder will be chosen early next year, with construction due to begin in the middle of 2016.

Mr Corbell said in the coming year, the Capital Metro project team would engage with shortlisted consortia in interactive workshops to evaluate their proposals, finalise contracts with the preferred consortium and prepare for construction commencement.

The funding will also be used to explore the option of extending the track through the City to Russell.

"An extension of light rail to Russell may bring significant benefits to Canberra and the light rail system, including an estimated uplift in patronage of around 30 per cent," Mr Corbell said.

"It would also present additional opportunities for local business participation with the project."

Bus network, roads the key to better ACT transport: Coe

Opposition transport spokesman Alistair Coe said the money to be allocated to the Capital Metro project in the upcoming ACT budget was just a fraction of the project's total cost.

"Unfortunately, this $50 million is just a drop in the ocean for the eventual $1 billion or so they're going to be spending on the Capital Metro project - a project that will only serve at most 1 or 2 per cent of Canberrans on any given day," he said.

Mr Coe said the Canberra Liberals believed the project should be put on hold, to give Canberrans the opportunity to have their say on this issue at the next election.

"We're very concerned that Labour Government is spending a huge amount of money that is totally unjustified and they do not have a mandate to do it. The Canberra Liberals firmly believe that the Government should stop spending," he said.

"They should not go ahead with light rail until the people of Canberra have had their say."

He said the most efficient way to improve transport in Canberra was to develop the bus network and make road improvements.

"It's also worth noting that every dollar we spend on Capital Metro is a dollar that doesn't go into health, a dollar that doesn't go into education, or a dollar that doesn't go into the police force," he said.