The completion date of the light rail line to Woden will be revealed in time for the ACT election.
The ACT government on Thursday committed to releasing an "indicative" timeline and milestones for light rail stage 2B, which is planned to link Commonwealth Park and the Woden Town Centre, on the final sitting day of the 10th Assembly.
The Assembly will sit for the final time on September 5, ahead of the October 19 election.
Transport Minister Chris Steel said the government had been up front and transparent with the public about the cost of building the city's light rail network.
"We've done that in an unparalleled way. Other state governments haven't done that for their projects, but we have. I have continuously said that we would publish light rail costs and time frames once contracts were signed and procurement was finalised to ensure the territory was in the best position to achieve value for money," Mr Steel said.
"And that's exactly what we've done."
Labor and the Greens agreed on amendments to a motion moved by the opposition spokesman on public transport, Mark Parton.
Mr Parton had wanted the government to release the full costsings of light rail stage 2A - which will link the Alinga Street terminus with Commonwealth Park - in June, and release the full costings and timeframe for stage 2B in August.
"We know that the numbers don't stack up on this project. But this government's too far down the rabbit hole to get out of it," Mr Parton said.
"And the lack of transparency has been remarkable. I know Mr Steel's going to stand up and protest that he's been as transparent as that perspex that used to separate us during the COVID times, but I just don't think that's the case."
The Canberra Liberals have vowed to cancel stage 2B of the project if elected in October.
Mr Parton also claimed the Woden light rail extension would cost closer to $4 billion, an amount he claimed was considerable even on "Planet Barr". The government has not released a cost estimate for the total project.
Jo Clay, the Greens' public transport spokeswoman, said she had negotiated for days with Mr Steel's office on amendments to the motion.
"We all want transparency. We want to know how this project is going and when it will be finished," Ms Clay said.
Ms Clay said she had been disturbed to read comments made by Mr Barr, reported in the RiotACT, in which the Chief Minister said the government had prioritised the Canberra Hospital expansion over light rail.
"We should be able to walk and chew gum," Ms Clay said.
In December, the government announced it had signed a $577 million contract for the 1.7-kilometre stage 2A light rail extension.
Mr Barr has previously indicated he expects the ACT will make a case to the Commonwealth for 50-50 joint funding for light rail to Woden.
"I think people understand complex infrastructure projects take time and that they would prefer us to under promise and over deliver rather than the other way around," Mr Barr said in December.
