Four guards have been taken to hospital after being assaulted by prisoners in the maximum security Auckland Prison (Paremoremo).
The attack happened at 4:25pm on Sunday.
The prison director, Andy Langley, says the injuries to the guards are not life threatening. He says the guards were admitted to hospital for assessment and treatment.
He says any prisoner who has resorted to violence will be held to account.
Waitemata police are investigating.