An inmate attacked at the country's maximum security prison yesterday received up to 20 stab wounds, the prison officers' union says.
The attack happened at Auckland Prison at Paremoremo yesterday morning and the inmate was taken to Auckland Hospital after it.
He received serious injuries but was later returned to the prison.
Corrections Department northern regional commissioner Jeanette Burns said staff intervened during the stabbing.
Corrections Association spokesman Beven Hanlon said their actions most likely saved the man's life but guards needed more protection.
The union's push for stab-proof vests for guards had paid off but they should also be given pepper spray, he said.