A contract for the extension of light rail to Woden is not set to be signed until after the 2028 election, leaving open the possibility for yet another campaign fought over the future of the project.
More detail for the project's timeline was quietly released on the final sitting day of the Legislative Assembly before the formal campaign began for this year's election.
The timing of the project could mean ACT voters will have had the chance to determine the future of light rail at four out of the last five territory elections.
Transport Minister Chris Steel's response to an Assembly petition said the government would finalise and consider the stage 2B business case, main works procurement and award a contract between mid-2027 and mid-2029.
Work on the final concept design and environmental approvals is expected to continue until mid next year, before detailed design and planning approvals are completed between mid-2025 and mid-2028.
The government expects construction to take about four years with a testing and commissioning phase of up to a year after construction is complete.
A Labor spokeswoman said the party's position on the project remained the same as it did when Chief Minister Andrew Barr in March said the government was working towards a construction period of 2028 to 2033 for light rail to Woden.
"ACT Labor will continue to work through each milestone necessary to bring light rail to Woden, including environmental, works, parliamentary and planning approvals. Timing will be subject to third party decisions which are out of the hands of the ACT government," the spokeswoman said.
"We'll further develop the design in line with these approvals and consider a business case for stage 2B next term.
"This is the most complicated infrastructure project the territory government has undertaken. It's a once-in-a-generation asset for Canberra, and there are a number of unique steps required to deliver the project."
Labor warned if the work was stopped by the Canberra Liberals, future stages of light rail would be set back by decades, or possibly generations.
The Canberra Liberals have vowed to halt work on stage 2B of the extension, which would link Commonwealth Park to Woden, saying they would redirect the spending. The opposition has claimed the project would cost about $4 billion.
Labor has not released an estimated price, saying it did not want to prime the market before a procurement process.
The Liberals said they supported light rail before the 2020 election, before reverting to the position they held at the 2016 and 2012 elections ahead of this year's polling day.
Jo Clay, the ACT Greens spokeswoman on transport, said the Greens would push harder to deliver light rail faster, including a larger project team, more ambitious deadlines and implementing a rolling program of planning and construction.
"We think it is madness to plan a stage then stop and then build a stage then stop, and then go out and procure another stage. We actually should just have the workforce to be planning what we need and building it on a rolling program," she said.
Mr Steel said the Greens' plan was a "fantasy".
