An inmate at the country's maximum security prison has had to be taken to hospital after being stabbed.
St John sent two ambulances to Auckland Prison at Paremoremo just after 11am today.
The prisoner was taken to Auckland Hospital with serious injuries.
In a statement, Corrections Department's northern regional commissioner Jeanette Burns said staff had to intervene to contain the incident.
Police have been informed and the inmate has since been taken back to prison.
The department said it would not tolerate violence, and those who used it would be held to account.
The Corrections Department said it was making no further comment because the stabbing was under investigation.