Officers confronted by 29 rioting inmates at the Spring Hill prison would have been overwhelmed if they had tried to use pepper spray, Corrections Department chief executive Ray Smith says.

Mr Smith today defended the actions taken by officers on Saturday when the rioting high security inmates set fire to buildings in a wing of the Waikato prison.

The Prison Reform Society said officers were unable to access pepper spray that was locked away, while the Corrections Association said officers needed tear gas to control rioters, Radio New Zealand reported.

Mr Smith said the prison officers who arrested the rioting inmates had "the tools that were best going to work", including helmets, shields, stab-proof vests and batons.


"The officers did the right thing in terms of removing themselves from the situation. They actually did incredibly well and did the thing we expect them to do," Mr Smith told Radio New Zealand.

"We know we always run the risk that a large group of prisoners might decide to take this type of action and we train for it."

Mr Smith said some Corrections officers suffered broken bones, and the ministry would investigate whether things could have been done differently.

"We came out of that situation with no casualties of prisoners or our staff, and I think they did a phenomenal job and they did everything they were trained to do."

Corrections Association president Bevan Hanlon told Radio New Zealand tear gas should have been fired into the prison wing to control the rioters, and officers should be allowed to carry pepper spray with them every day.

"We should have filled that compound with tear gas, and then we should have gone in and mopped-up what was left over."