A group of teenagers in Hawke's Bay Regional Prison caused $1 million worth of damage in 24 hours of rioting and disorder.
The cost of the riot last August, during which the young inmates spent most of their time on the roof, was provided to the Hastings District Court on Friday by Crown prosecutor James Bridgman.
He was responding to a question from Judge Bridget Mackintosh, who was sentencing Paul Makoare on charges of rioting and causing intentional damage.
Makoare was just 18 and a remand prisoner when the riot broke out in the High Security Youth Unit of the jail on 1 August, 2022.
The unit catered for young men under the age of 20.
The disorder started when officers told inmates in the unit's Wing 2 they would not be allowed outside for exercise until they had cleaned graffiti off the walls.
Makoare was in Wing 1, so was not initially involved. However, he joined in after Wing 2 prisoners climbed up onto the roof and gained access to the area where he was held.
No one was seriously injured during the riot, but court documents say the inmates threw 34 chisels at staff, among other items, and one object struck a 71-year-old Corrections officer in the back of the neck.
Over the next 24 hours, they refused to come down from the roof and broke into a number of rooms in both wings, causing extensive damage and daubing them with graffiti.
They took various objects from rooms to use as weapons and projectiles, including the chisels, a trolley, food, electrical equipment, wood, metal pipes and door handles.
These objects landed close to Corrections officers and sometimes struck their shields.
The rioters also threw objects at prison vehicles moving around the jail.
The youth unit has not reopened since the riot, according to information made available to the court.
Defence counsel Susanne Lott argued a prison term for the rioting should be served concurrently with the sentence of 27 months that Makoare is already serving for aggravated robbery and other offences.
But Judge Mackintosh said offending in a prison environment deserved a "stern response".
She accepted Bridgman's submission that the new prison term should be served cumulatively. She added 10 months to Makoare's current sentence.
"It's a real shame that a young guy like you now is in custody and for quite a while," she said.
Judge Mackintosh noted Makoare, now 19, already had three convictions for aggravated robbery and warned him he did not want to spend most of his life in prison.
"There's way more to life than that," she said.
Makoare had pleaded guilty to the charges, for which Judge Mackintosh gave him credit.
"You've put your hand up and owned up to what has happened."
The other five men charged after the riot are being dealt with separately by the courts.
* This story originally appeared in the New Zealand Herald.