A prisoner has been injured after being assault by another prisoner in the recreation yard of a Northland corrections facility.
The attack, which "appeared to be unprovoked", took place at the Northland Region Corrections Facility/Ngawha Prison at 2pm on Tuesday, Northland Region Corrections Facility prison director Michael Rongo told 1 NEWS in a statement.
The condition of the prisoner is unknown as the incident remains under investigation.
Rongo said the assault occurred "while staff were occupied with another prisoner outside of the yard".
"When they returned, the victim of the assault was injured. Staff immediately provided the man with first aid and was assessed by Health Services at the prison before being taken to hospital by ambulance for treatment.
"He returned to the prison the following day and was placed in a different unit."
The prisoner involved admitted to the assault after being identified, and was "relocated to the management unit and placed on Directed Segregation".
"He will be charged with misconduct and the incident will be referred to the police for further investigation," he said.
Rongo said while the assault occurred "during a short window of time when staff were not physically in the yard", the area is under constant monitoring by CCTV.
He said the unit was fully staffed on the day, barring the "short period of time in the afternoon" where one corrections officer was preoccupied with another prisoner outside of the yard.
Staff safety plans were in place to account for their absence, and "no escalated tension in the unit had been identified".
"We have a zero tolerance for violence policy, and any violence or assaults against other prisoners or staff is not tolerated in prisons. Any prisoner using such behaviour will be held to account for their actions, including facing criminal charges," he said.