The father of a Spring Hill Prison inmate says last weekend's riots were sparked by a fracas between the 19-year-old and guards after they caught him with home brew.
As word of the fiery uprising in North Waikato filtered through to other jails last Saturday, Paremoremo maximum-security inmates jammed the gate on a landing and tried to start a fire.
And one guard at Ngawha Prison near Kaikohe - scene of a clash between staff and inmates last July - told the Herald on Sunday that a copycat incident could happen at any of New Zealand's jail.
Corrections Minister Anne Tolley has commissioned an inquiry into the Spring Hill riot.
Until that is completed, Corrections is refusing to respond to claims that the Killer Beez and Mongrel Mob gangs were involved in the uprising, and to the father's claim that a guard broke his son's arm.
Tolley, though, has already suggested honouring prison officers for bravery - even before their handling of the riot has been investigated. "They risked their lives and should be recognised," she wrote by hand on a briefing note, issued to the Herald on Sunday.
Prison reformers insist double-bunking and a dearth of activities are triggering tensions.
The inmate's father said prisoners exploded after hearing his son, serving a nine-year term, was assaulted when found with home brew.
"My son ended up in hospital. The screw snapped his arm."
The father said his boy had since been transferred to Paremoremo with multiple stitches in his head.
"All his property is gone. He's got no clothes, no nothing left, from the inmates cranking the fires and all that. His cell got burned out."
Last Sunday, the Corrections Department moved 117 prisoners to Paremoremo, Mt Eden and Waikeria.
Some opposition MPs said they, too, had been told an incident involving home brew might have sparked the crisis. Tolley, though, said that was just one among many rumours.
In the briefing note, Corrections said fixing Spring Hill meant other jail refurbishments might have to be postponed. It said it was considering suing prisoners for damages.
Tolley maintained most of the unruly inmates last week were members of the Killer Beez, a gang said to have a growing prison presence.
New Zealand First MP Asenati Lole-Taylor - a former Corrections rehabilitation adviser - said a cohesive group of Killer Beez causing unrest suggested an intelligence failure on the part of the department.
She said it was well known that barring contact between members of the same gang was sensible, to prevent any group growing too dominant, bullying other inmates or undermining authority.
But Labour Party corrections spokesman Kris Faafoi was sceptical. "The reports I've heard are that it may just have involved one group who got hold of a substance, or made a substance they shouldn't have."
Prison reformer Peter Williams, QC, said Spring Hill inmates and their families were blaming boredom and harsh conditions.
At Paremoremo, an email sent on behalf of high-profile inmate Arthur Taylor complained of under-staffing, smoking bans and a lack of activities.
"We didn't get out on Saturday because officers had to go to assist at Spring Hill," he wrote.
"A few prisoners on my landing were very aggrieved at being locked up for two days straight and staged their own protest by locking the landing gate and starting a fire."
He spoke of ominous tensions in his jail. "You could cut it with a knife. I've never known prison conditions to be worse than they are today."