"The objective to successfully bring this situation to an end with minimal disruption and with minimal injury to staff and prisoners has been achieved, although the corrections officers' injuries may include suspected fractures."
She said investigations would continue into the riot, and charges were likely to be laid against several prisoners.
The rioting began just after 11am.
Gang tensions are believed to have sparked the on-going prison riot at Spring Hill jail south of Auckland, where inmates are setting fires and damaging cells.
The mayhem was contained to two cell blocks and the Department of Corrections said early indications suggested the incident was gang-related.
Eyewitnesses have seen plumes of smoke billowing from the cell blocks.
"Specialist teams trained to deal with such events are on site and one of Corrections' most senior commissioners, Jeanette Burns, is co-ordinating the response there," Corrections said in a release.
Burns referred to the riot as a "serious" and "regrettable" event.
An ambulance spokesman said police had informed him of a riot at the prison.
"Police are treating it as quite a large event,'' he said.
"It is believed that someone has been stabbed.''
Ambulance crews remained at a safety staging area.
"We're just there doing what we can. I'm not too sure if our crews are tending to any patients at this stage.''
