Prisoner-on-prisoner assaults at Otago Corrections Facility (OCF), near Milton, jumped 50% in three years, while assaults at Invercargill Prison rose a massive 88%, information obtained under the Official Information Act shows.
The Department of Corrections would not put up anyone from OCF for an interview, but in a statement, acting National Commissioner Topia Rameka said more gang members in prisons, more inmates on remand, and more prisoners with histories of meth use were contributing to violence in prisons.
There were 81 prisoner-on-prisoner assaults at OCF in the 2019-20 year, five of which were serious. In the 2017-18 year, there were 54 assaults.
At Invercargill Prison, assaults rose from 25 to 47 over the same period.
Mr Rameka said Corrections had a zero-tolerance policy towards violence.
"We have invested significantly in training and tools to keep our people safe. This includes tactical skills, such as de-escalation, through to the introduction of stab resistant body armour, on body cameras and the expanded deployment of pepper spray," he said.
"The goal is always to manage a potentially volatile situation in a manner that minimises the likelihood of violent behaviour."
He said both prisoners and staff were encouraged to report all assaults, and anyone who committed an assault would be held to account.
"This may be through internal misconduct charges, a change in security classification, or referral to police for consideration of criminal prosecution."
Corrections recorded health and safety incidents on a tracker system. That included events involving prisoners, staff and contractors, and tracked any injury incidents, non-injury (near miss) incidents and events relating to uncontrolled hazards.
There were 680 events recorded on the health and safety tracker at OCF between January 1 and November 30 last year.
Corrections Association New Zealand president Alan Whitley said a lot of injuries staff received happened while they were trying to break up fights between prisoners.
OCF staff had reported an increasing number of gang members in the area.
But, he said, prisons in general were more violent than they were in the past because offenders at the lower end of
the scale were receiving more community-based sentences.
He wanted all assaults on Corrections staff, regardless of how serious, to be reported to police rather than going through internal processes.
He was also supportive of a proposed Bill that would mean tougher sentences for people who assaulted first responders, including Corrections officers.
