But Justice Minister Shane Rattenbury said building new cells wouldn’t alone fix the problem, forecasting wider reforms to the territory’s criminal justice system as part of a new push to address the issue.

A record 507 inmates were held at Alexander Maconochie Centre in June this year, as average daily prisoner number rose to 474, almost double the amount from 2010.

The prisoner squeeze comes just two years after the completion of a $47-million expansion of the Hume jail, which created an extra 112 beds.

As the prison continued to fill, the government last year commissioned a $275,000 feasibility study to assess options.

The report went to government earlier year but has yet to be made public.

Mr Rattenbury last week refused to release the report, saying it was still being considered by Cabinet.

He said the study canvassed a range of options that were being weighed up by his colleagues, including another expansion of Canberra prison.

Mr Rattenbury said building extra beds was part of the solution, but warned they would be quickly filled without a rethink of the government's approach to addressing incarceration rates.

Recidivism rates in the ACT rose six per cent in 2017-18, with more than 44 per cent of prisoners returning to jail within two years of their release.

Mr Rattenbury forecast a greater investment in programs to support prisoners being released on bail, as well as more help to ensure they could meet bail conditions.

"What we are seeing in the ACT [increasing prison population] is happening across the nation and there are different views on what is driving that, but certainly there is a clear sense that the increased focus on family violence and methamphetamine are two of the drivers," Mr Rattenbury said.

“If we don't think about doing things differently then the prison will continue to fill.

“We need to look at this in a holistic way, that’s not to say that we will not need more beds, but the answer cannot simply be just building more beds.”

Mr Rattenbury said the government would announce its plans in the coming months, including a range of short-term measures to ease immediate pressure on prison bed spaces.

He would not be drawn on how much any of the measures would cost.

ACT Liberals corrections spokeswoman Giulia Jones said the Barr government had failed to plan for the territory's growing prison population.

"Only three years ago Canberrans paid $50 million to expand the prison and already it is on the brink of another overpopulation crisis," Ms Jones said.

“The government’s failure to plan for prison population growth has already cost Canberrans a huge amount of money. Now it appears taxpayers are going to have to pay even more.

“It is about time Minister Rattenbury provides some vision and long-term planning.”