A Serco staff member at Mt Eden prison has been suspended after being caught fighting an inmate.
Footage of the incident was discovered as part of a review into the prison being carried out after allegations of fight clubs between inmates and drug smuggling.
A spokeswoman for Serco, a private British company that was contracted to operate the prison, confirmed an officer had been suspended, pending a disciplinary hearing.
"The safety and security of staff, prisoners and visitors in Mt Eden Corrections Facility is paramount and we have zero tolerance for violence."