Heads could roll within NSW's embattled prison system, the state government has warned, after an inmate was allegedly bashed by another in a cell they weren't meant to share.
Corrections Minister David Elliott on Thursday confirmed the two men were placed in the same area of Wollongong's holding system while awaiting a court hearing despite them being subject to a "non-association order".
One of the inmates was allegedly attacked and suffered minor injuries.
"I've demanded an immediate explanation from Corrective Services about how this has happened, and reassurance that it will not be repeated," he told AAP.
"If departmental disciplinary action must be taken, then it will be."
Corrective Services NSW Commissioner Peter Severin said there would be a full investigation into the attack.
CCTV and security systems are being reviewed.
"We are deeply regretful these inmates were placed together and will perform a thorough review of the allegations," he told AAP.
"We manage thousands of inmates in protective custody and on non-association orders using strict guidelines to ensure they are moved safely."
The investigation follows allegations some NSW prison guards have had sexual and romantic relationships with inmates.
A special task force, to be led by former NSW Police assistant commissioner Mark Murdoch, was set up to investigate alleged misconduct over the past decade.
Corrective Services is also working to accommodate a swelling inmate population while restructuring its workforce - including laying off middle-management - amid fierce opposition from unions.
The coalition government insists it is investing in the system while creating a workforce with more boots on the frontline.
Australian Associated Press