Chief Minister Katy Gallagher is discussing the extreme measure with the ACT's bureaucracy as one option for speeding up the project, which has been dragged out by years of debate over the need for such a facility and multiple increases to the estimated cost.

The government will also consider the use of controversial call-in powers and a select tender process as alternative measures for bringing the completion date forward.

The ACT opposition said on Sunday it would consider any option to help realise the project, which Opposition Leader Jeremy Hanson said had been an "absolute catastrophe" to date.

Fairfax Media revealed last week that the completion date for the 25-bed medium-secure facility had been pushed back by more than a year to May 2017.

The revelation followed the first prisoner suicide in Canberra's jail last week.

A 30-year-old inmate died in his cell in the prison's health centre on Tuesday night, just one month after authorities were warned that he was at risk of self-harm.

It is still unclear why the inmate was locked in the prison's health centre, which is understood to be inappropriate for those at high risk of self-harm or suicide, rather than the specifically designed crisis-support unit.

The prison was close to capacity on the night of the death, however, the government has refused to answer questions about whether the crisis support unit was full or whether the prisoner was still identified as at-risk.

The death in custody followed a spate of assaults at Canberra's adult mental health unit and revelations that at least one patient this year had been sent to prison for an incident at the unit.

Ms Gallagher said a 2017 completion date was not acceptable and the government was looking at measures to bring the 25-bed medium-secure forensic unit forward. Under the government's original plans, a 15-bed high-security facility for people found not guilty of crimes due to mental illness was to be built by March 2016.

Ms Gallagher said she had raised the possibility of using project-specific legislation that would allow the Legislative Assembly to approve the project and curtail the planning process.

The measure is a step above the call-in powers granted to Sustainable Development Minister Simon Corbell.

The government has previously used project-specific legislation to approve the construction of the Gungahlin Drive extension.

"That's at an extreme end and then there's probably other steps within that planning arrangement that we could look at," Ms Gallagher said.

"Speeding it up will be contentious."

Ms Gallagher said other options for consideration included a select tender process involving only a handful of companies or lobbying Mr Corbell to use his call-in powers to approve the project.

The Chief Minister said whichever option the government pursued would depend on the level of support from the opposition.

The project is likely to be an issue for the Assembly at its next sitting in August.

Mr Hanson said the opposition supported the project but the planning of the facility had been "a disaster" that had resulted in the jail and the adult mental health unit being used as a "stop gap".

"In terms of a failure of governance, this [project] has been a disaster," he said.