Police say a "complex investigation" that could take several months is under way into the six-day riot at Waikeria Prison, which ended yesterday.
The 16 inmates who destroyed the top jail surrendered peacefully at 12.37pm and now the facility is unusable, the Corrections Minister Kelvin Davis says.
Rioting began after fires were lit in the exercise yard on Tuesday afternoon. The inmates took over the jail in less than 24 hours.
Advocates say they were protesting against unhygienic and dehumanising conditions - claims vehemently denied by Corrections.
Police were not in a position to comment on any charges the inmates might face last night, a spokesperson said.
And with the top jail being treated as a crime scene, Corrections were not able to comment specifically to avoid prejudging the outcome.
Barrister Gary Gotlieb says police investigators face a strenuous task.
"We don't know the facts yet and it's going to take time to work out what actually did happen," he said.
"If [the inmates] just got themselves on the roof and not really hurt or threatened prison officers, we're getting more to the property type of offending.
"We are going to have to wait and see what the police are going to charge them with. It's going to be a matter of watching the space."
The prison went into lockdown soon after rioting began last week, with 200 prisoners soon evacuated from the top jail and taken to other prisons.
The near week-long riot only ended after Māori Party co-leader Rawiri Waititi met the inmates.
"They were ready to come down," Waititi said. "Naturally, they were tired and hungry but still very determined to see change."
Most of the 16 were members of the Mongols and Comancheros gangs, with five of the men deported from Australia.
Department of Corrections chief executive Jeremy Lightfoot says they are not aware of any complaints made by the men in relation to their living conditions.
"There is no excuse for what these men have done," he said.
"The actions by the men exposed them, other prisoners, our staff, and emergency services to significant danger."
Davis does not believe the inmates were rioting over living conditions, he told the media yesterday afternoon.
The minister thanked emergency services, Corrections staff, kaumātua, and tangata whenua for their efforts, support and guidance over the standoff.
Davis said he chose not to speak out during the siege because he did not want to encourage similar behaviour from other prisoners, saying the inmates wanted political attention from the rioting.
Asked about his apparent lack of communication amid the rioting, Davis said his role was to leave the response to the experts.
Corrections incident controller Jeanette Burns said staff tried to end the rioting on Saturday night but were met with force by the inmates.
After retreating to prevent injury, Corrections received word about 11.30am yesterday that the inmates were ready to surrender and just over an hour later all were off the roof and secured.
"At all times, Corrections were in control of the situation," Burns said.
Two reviews have been commissioned into the rioting, Lightfoot said.
The first is an operational review by the chief custodial officer, which should be completed within three months.
The second, by the office of the chief inspector, should be completed within six to nine months.
ActionStation, People Against Prisons Aotearoa, and JustSpeak called on police not to press additional charges against the inmates.
They said the men were protesting against breaches of human rights and Corrections had to address the issues to ensure their safety and wellbeing.
The Human Rights Commission has called for an inquiry, with Chief Commissioner Paul Hunt saying the siege was not a one-off.
"Whatever triggered this protest, poor prison conditions are a vital part of the context," Hunt said.
"Last August, the Ombudsman published a report on Waikeria and concluded that the high-security complex is no longer fit for purpose.
"Only last month the Human Rights Commission published a report that demonstrated serious failings in the prison system."