The Corrections Department says the 29 prisoners who rioted at Spring Hill Prison in North Waikato on Saturday used poles from volleyball nets as weapons.
A police road block near Spring Hill Prison. Photo: RNZ
The high security inmates went on a rampage in two cell blocks causing damage that could cost more than $1 million and take six months to fix.
One hundred and seventy prisoners have been moved to other prisons because of the damage.
Corrections Northern Regional Commissioner Jeanette Burns says the prisoners got aggressive and violent and officers had to pull out for their own safety.
She says prisoners broke into a store and were able to arm themselves with cleaning implements and poles which they used to smash windows in the unit, as well as lighting some fires using cleaning agents, plastic tables and blankets.
Ms Burns says the prison has been in partial lockdown on Sunday but everything has been calm.
Corrections Department chief executive Ray Smith says his officers did an amazing job.
"I think risked their own lives to save the lives of prisoners who had started the fire and then got themselves trapped in the compound, so our staff followed the training, followed all the procedures."
Mr Smith says there was no inkling that trouble was likely to erupt on Saturday.
Anne Tolley (right), Ray Smith and Jeanette Burns at a media conference. Photo: RNZ
Corrections Minister Anne Tolley visited the prison on Sunday.
She says prison officers risked their own lives to rescue prisoners from being burnt alive.
Mrs Tolley says the officers followed prison policy to the letter.
"I'm really pleased to be standing here today that I don't have to go and talk to any families who've had a prison officer seriously injured or whose life has been lost and that could have happened, those guys did put their lives at risk at one stage last night to make sure they got prisoners out of cells."
Three officers were injured in the riot and two prisoners. None of them seriously.
