Corrections said over 200 inmates had to be moved away from the burning unit to safety. So far, only four of the 21 responsible have surrendered, Lightfoot said.
"We are clear about the criminal wanton damage that these individuals have undertaken on property and exposed so many people to potential loss of life."
Up to 70 firefighters, multiple ambulances and specialist advance control and restraint teams have been dispatched from all over the North Island since the riot began.
Callers from within the jail told Newshub conditions in it are inhumane, a sentiment shared by the very guards they're clashing with. Corrections Association president Alan Whitley admitted: "It's beyond its use by date."