President Fiona Carrick said the scale of Woden's high-rise housing boom had fast-tracked the need for a "high-capacity transport solution" to service Canberra's south.

But with the government confirming it would split the light rail expansion into two stages, Ms Carrick feared its arrival might yet be pushed back.

She was also concerned about an apparent "lack of transparency" surrounding the government's decision to commit to the project before finalising a business case.

Fronting the media on Friday, Chief Minister Andrew Barr and new Transport Minister Chris Steel were confident passengers would be riding light rail to Woden by 2025, as previously forecast.

Mr Barr said fast-tracking work on the second stage of light rail between Alinga Street and Commonwealth Park would help get the project off the ground, rather than wait for federal government approval for the entire route to Woden.

Stage 2A would only involve negotiation with the National Capital Authority and ACT planning authorities, together with the Commonwealth Environment Minister.

Stage 2B - which crosses the lake and runs through the Parliamentary Zone to Woden via the State Circle - would also have to pass through the federal Parliament.

Mr Barr said Scott Morrison's surprise federal election victory had been major factor in his government's decision to split the project in two.

Then Opposition leader Bill Shorten had promised $200 million towards the project ahead of the May 18 election, while Mr Barr was confident of a quicker passage through federal parliament with Labor in power.

On Friday, Mr Barr said he did not expect the federal government to throw major roadblocks in the way of stage two.

He played down the risk of the project being stalled at Commonwealth Avenue Bridge.

ACT Property Council executive director Adina Cirson praised the government's bid to fast-track the project by splitting it up, describing it as "out of the box thinking".

"We had always been hoping that stage two would follow immediately from stage one," Ms Cirson said.

But Opposition transport spokeswoman Candice Burch said the government was yet to justify the new approach.

"We still haven't seen the business case and the big question is whether it is going to cost more splitting it up into two stages," Ms Burch said.

Asked if the Canberra Liberals were prepared to lobby their federal colleagues if the parliamentary approvals process stalled, Ms Burch said she would first need to see a detailed businesses case before any action was taken.

"They need to release the business case to prove to Canberrans that this route is the best option," she said.

"We are constantly hearing from people saying 'why aren't we building [light rail] to Belconnen or the airport."

National Capital Authority chief executive Sally Barnes said the extension to Commonwealth Park, if approved, would help attract visitors and locals to the precinct for events and recreation. The authority would continue to work with the ACT government to navigate the "more complex issues" associated with getting light rail across the lake.