Police are investigating the assault of four Corrections officers at Christchurch Men's Prison on Wednesday afternoon.
The attack involved at least seven prisoners who are reported to have been in possession of a weapon at the time.
Acting Prison Director Russell Watkins says the situation was brought under control quickly.
"The situation was swiftly brought under control and the officers were treated on site with follow up treatment from their GP," he says.
"Corrections takes the issue of violence in prisons extremely seriously and our priority is staff safety.
"The Department [of Corrections] will not tolerate prisoners using violence against staff or other prisoners, and the prisoners involved will be held to account for their actions."
Mr Watkins says attacks can be unpredictable but staff are adequately trained for such incidents.
"Prisoners can be volatile and unpredictable and many have long histories of antisocial behaviour and resort to violence with little warning and our staff carry out their work in the knowledge that assaults can happen," he says.
"Frontline Corrections Officers receive specialist tactical and de-escalation training and personal protective equipment such as stab proof vests."
Police say the investigation is on-going.