A prisoner has been hospitalised after a fight at a high-security yard at Rimutaka Prison.
The prison's acting general manager Rob Anesi told Newshub the fight broke out at around 8:45am on Sunday, June 30.
"Staff responded immediately, entering the yard within a minute of the fight starting to remove the injured prisoner from the yard," he said in a statement on Monday.
"Health staff were in attendance within three minutes to provide medical support to the man. An ambulance was called and the injured prisoner was transferred to hospital where he remains."
Anesi said the prisoner is awake and has been talking to staff. Police have been notified and Corrections will carry out a review.
"Violence in prison is not tolerated and any prisoner using such behaviour will be held to account for their actions, including facing criminal charges," he said.
"Prisons can be volatile environments, and we are constantly working to ensure our prisons provide the safest environment possible for staff and prisoners.
"Many prisoners have long histories of antisocial behaviour, and can behave unpredictably and act without warning. Over 80 percent of the prison population have convictions for violence in their offending histories."