The ACT government has commissioned a review into the delivery of its $160 million city courts precinct redevelopment, amid fresh questions about the lengthy delays which have dogged the landmark project.
The project's second stage is not expected to be completed until late this year, more than 15 months behind schedule.
The project is being delivered by a private consortium, known as Juris, which is bearing the cost for the overruns.
At an annual report hearing on Wednesday morning, shadow attorney-general Jeremy Hanson asked government officials if it was attempting to get to the bottom of "what's gone wrong".
Major Projects Canberra executive Lloyd Esau said the government had commissioned a "lessons learned exercise", which would assess the delivery of the project once it was complete.
Mr Esau noted that the two groups which bid for the contract had anticipated similar construction timeframes for the two-stage project.
He said Laing O'Rourke, which is the construction arm of the Juris consortium, had suffered a range of "set backs" since winning the tender in 2016.
"There is a combination here of the fact that they underestimated the complexity of the project and overestimated the speed at which they would progress at various stages of the build," Mr Esau told the hearing.
"They encountered difficulties and they struggled themselves to maintain the progress of the project."
A project status report tabled last month in the ACT Legislative Assembly noted that in light of potential delays, the Supreme Court was investigating "alternative arrangements" for the territory's soon-to-be-established drug and alcohol court.
When The Canberra Times sought further information on those contingency plans, the government said the federal court, military court and Queanbeyan courthouse could be used if required. It emphasised that the other locations weren't expected to be needed.
The government said existing Supreme Court courtrooms would be used if the new space wasn't ready.
On Wednesday, Attorney-General Gordon Ramsay said he wanted to "make it clear on the record" that drug and alcohol cases would be heard at the city law courts.
The project's second stage includes the refurbishment of the two remaining courtooms in the heritage-listed court building, as well as mediation suites, hearing rooms and space for justice support groups.
A new four-storey Supreme Court building, which was the centrepiece of the revamp's first stage, held its first sitting on October 15 last year.
Under the terms of its contract with the ACT government, Juris is responsible for maintaining the precinct for 25 years. The government will pay off the development over that time.