Corrections will no longer use the controversial 'tie-down' method of restraining prisoners at risk of hurting themselves or others.
The practise was informally ended in 2016, chief custodial officer Neil Beales told Stuff, and was now being banned in prisons nationwide.
"The use of tie-down beds was always a last resort to protect prisoners from escalating extreme and prolific self-harm or where their behaviour posed a threat to their life, or the safety of staff and other prisoners," he said.
The ban comes two years after Corrections admitted the practise breached torture rules. One inmate had been tied down for 16 hours on 37 consecutive nights, a report by the Chief Ombudsman found, despite only getting permission from medical professionals for one night. He was often tied down to ease the workload on staff in the evenings.
Threats of being tied down were also wrongly used to get prisoners to comply with staff demands.
"I accept that some mistakes were made in the use of the tie-down bed in this case and its use crept from being a last-option to a tool for managing the prisoner's health and complex behaviours," Corrections chief executive Ray Smith said at the time.
Chief Ombudsman Peter Boshier said he was disappointed it took so long for Corrections to formally end the practise.
"Since that time, I think there has been an acceptance that we were right," he told Stuff.
He blamed a lack of mental health services in prisons for the increasing reliance on tie-downs.
Newer facilities are being built with mental health services in mind, such as at Auckland Prison in Paremoremo.