One of the key instigators in New Zealand's largest-ever prison riots has admitted his role in the six-day incident that caused at least $50 million worth of damage

And court documents reveal that it was a dispute over razor blades that ultimately led to 17 prisoners setting fire to wooden structures, throwing cups of urine at Corrections staff, and threatening to assault them between December 29, 2020, and January 3, 2021.

Matangairau Cuff today pleaded guilty to three representative charges of being a member of a riot unlawfully damaging property, reckless damaging property by fire in circumstances knowing danger to life would ensue, and assaulting various people with various objects as weapons.

He was declined bail and remanded in custody for sentencing next year.

Cuff, whose name suppression was lifted this morning, was in Waikeria Prison on remand when on the morning of December 29 there was an incident in the exercise yard involving disposable razors that he refused to hand over to Corrections staff.

A number of co-defendants went to his support.

When a principal corrections officer advised him they would all be returned to their cells early if the razors were not surrendered, the group said that they were not going anywhere and were ready to fight.

Eventually, one razor was handed in and the situation was de-escalated, with the prisoners allowed to continue to stay outside until 2pm as was routine.

However, at midday, another co-defendant contacted news media and announced their collective effort to riot against prison conditions.

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Subsequently, the nine defendants in the exercise yard, including Cuff, set fire to wooden structures and seats, covered security cameras with toilet paper, prevented Corrections staff from extinguishing the fires, threw cups of urine at them, and threatened to assault them if they attempted to enter.

A second phone call was made to the same news media outlet at 2.19pm, stating that they intended to "go to war".

After that call, Cuff escaped the yard by climbing onto the roof.

Waikeria Prison was almost completely destroyed after a six-day riot which began after prisoners refused to hand over disposable razors to Corrections staff. Photo / Brett Phibbs

Nine others followed and Cuff then unsuccessfully attempted to inspire the other 12 remaining in the yard to join him.

He then began liberating prisoners housed in the upper levels using an iron bar to smash through cell windows.

Twelve were freed and eight of those chose to join the riot, while the remaining prisoners were evacuated.

Over the next three days, from December 30 to January 1, Cuff continued to riot across the rooftops, along with 16 others, lighting fires, vandalising structures, and throwing items at corrections staff.

He also accessed the facility's armoury, where he seized protective body armour, shields and a grinder.

He also fortified an area behind the prison chapel as sleeping quarters and storage of valuable items.

About 4.15pm on December 31, one co-defendant surrendered.

However, about 10.30pm on January 1 a confrontation occurred between four defendants Armed Offenders Squad members, and advance control and restraint officers.

A rubber bullet fired by AOS hit one of the defendants in the torso and they all retreated.

Afterwards, fires erupted on top of several buildings, the kitchen was set on fire and defendants threw objects at Corrections staff and firefighters.

At 7pm on January 2, teams of Corrections staff entered the prison.

Fires erupted behind the barricade at the prison chapel, forcing further evacuations as fire swept through.

The riots caused "near complete destructions" of the prison.

The rioters eventually gave up on January 6.

- Belinda Feek, Open Justice