The Public Transport Association of Canberra chair Ryan Hemsley said the cash boost was a sign that light rail wars of 2012 to 2020 were over.

"This is a clearest indication yet that the federal government supports the extension of Canberra's light rail network from Civic to Woden," he said.

"I am very grateful that we can move the conversation from 'should we build it?' to 'how do we build it?'."

Stage 2A will expand the service from Alinga Street to Commonwealth Park and is the first phase of light rail from Civic to Woden.

Despite the Commonwealth's funding commitment and gaining environmental approval, the ACT government is still awaiting approval from the National Capital Authority and ACT Planning.

Transport Minister Chris Steel said he expected the NCA to approve the project about quarter three this year.

Work is expected to commence on Stage 2A in 2021-22. The ACT government has not released an expected completion date for Stage 2A.

Mr Hemsley said he was confident the government would release a firmer timeline for the completion of Stage 2A following NCA approval.

Master Builders ACT chief executive Michael Hopkins said he welcomed the funding for Stage 2A.

"Local contractors are looking forward to the opportunity to help deliver Stage 2A of the light rail project, including early works to raise London Circuit," he said.

"This project has the potential to create thousands of local jobs, and the MBA is pleased to see the ACT and federal government working together to deliver infrastructure and support the local construction industry."

Chief Minister Andrew Barr, Transport Minister Chris Steel, senator for Canberra Zed Seselja and Deputy Prime Minister Michael McCormack presented a united front when they announced the funding for the project on Wednesday.

"All aboard this congestion-busting, job-creating, hope-building and confidence-creating project," Mr McCormack said.

"This is what happens when governments collaborate.

"The Canberrans walking by, they don't care what particular stripe of government is up on the hill or here in Canberra. They just want to get things done."

Mr Steel said Stage 2A would be a disruptive program in the short term, but would "provide long term benefits for our city".

Regarding stage 2B, Mr Barr said the project required complex Environment Protection and Biodiversity Conservation approvals before work could go ahead, along with approval from both houses of Parliament.

Gesturing to Mr Seselja and Mr McCormack, Mr Barr said he'd be "calling on these two gentlemen for their advocacy, support and a vote for the project when it ultimately comes before Parliament".

Despite his previous stance against light rail, Mr Seselja said the people had spoken and that "the debate on light rail was over".

"The question now is making it work and, of course, making it accessible to as many Canberrans as possible," he said.

"I've always said once the first stage of light rail was completed it made absolute sense to expand it and turn that into a network."

Mr Seselja said he would continue to push for infrastructure funding for Canberra, for both public transport and car-based transport.