Fires are still smouldering at Waikeria Prison in Waikato as a stand-off with more than a dozen inmates continues more than 24 hours after it began.
The Department of Corrections says it will not be sending any staff into an "unsafe situation" and it is prepared to wait to resolve the impasse.
Seventeen inmates remain involved who have access to the "top jail"” part of the prison, the oldest part of the site built in 1911 and now rendered useless.
Inmates will never use its 250 beds again because of the damage. However, the unit was due to be replaced in 2022.
Officials said 212 inmates have been evacuated from the site.
In a media briefing at the prison gates this afternoon, Department of Corrections chief executive Jeremy Lightfoot said there was wanton disregard for safety and wellbeing of other inmates and staff.
He said the department is preparing "a range" of plans.
"We will not be sacrificing my staff by going into violence," he said
Mr Lightfoot said it was the media that alerted the department to the riot before it started.
He would not go into specifics about what damage there has been.
Fire and Emergency NZ said that, while remaining fires at the prison are not blazing, they are still smouldering.
About 45 fire staff and up to 12 fire engines are still at the prison.
At the peak of the fire there were about 70 staff and 15 appliances.
The 17 inmates involved have no access to additional food or water and the Corrections Department says such access is likely to form part of the negotiating strategy.