A central Auckland prison has been on lockdown since two guards were assaulted by a prisoner this morning.
A Department of Corrections spokeswoman said a prisoner from Mt Eden Corrections Facility had been placed in segregation following an "unprovoked assault" on two officers about 11.15am today.
Both staff members were punched by the prisoner and knocked to the ground.
Other staff moved quickly to bring the situation under control and both officers were taken to a medical centre for treatment and are now at home.
They are being provided with ongoing support.
Following the assault the prison was locked down, with the exception of legal visits being allowed to continue.
The site was locked down for the night, as per standard evening hours and would resume operating as normal tomorrow morning.
"No assault or violent behaviour is tolerated, and any prisoner who resorts to this behaviour will be held to account," the spokeswoman said. This could be through internal misconduct charges, a change in security classification, or referral to police to consider criminal prosecution.