Prisoner accidentally released, recaptured from Alexander Maconochie Centre

The release of the detainee - who had completed his first sentence but should have stayed in prison on a further remand warrant -followed four escapes, two deaths and a violent bashing at the centre since April last year.

Saturday's accidental release was due to an "administrative error", according to a Justice and Community Services spokesman.

Opposition corrections spokeswoman Giulia Jones wrote to Chief Minister Andrew Barr urging him to consider whether Mr Rattenbury was fit for the portfolio.

"I have grave concerns that as a representative of the Greens party, Minister Rattenbury is not an appropriate fit for the role of Minister of Corrections," she said on Thursday.

"I am concerned that inmates, prison staff and the wider community are being put in danger.

"I have asked the Chief Minister to give this the serious consideration that it deserves. I am awaiting his response."

Mr Barr said: "I have full confidence in Mr Rattenbury as Minister for Corrections."

The Justice spokesman said the man was now in police custody after ACT Policing was sent notice of a wrongful release.

"ACT Corrective Services is currently conducting a review of processes to ensure that this error does not recur," the spokesman said.

Six prisoners have escaped since April last year. Four of the men were being treated in the Canberra Hospital at the time of their escape while the remaining two used a ladder left by construction workers to scale three fences.

Prisoner Steven Freeman died in May 2016 just days after beginning the prison methadone program, despite there being no record he had ever used heroin.

Detainee Mark O'Connor died in May this year with a cocktail of drugs and medications in his system, including ice and buprenorphine.

Five prisoners were hauled into court on Thursday accused of bashing two brothers in the jail in August.