More fires have burned overnight at Waikeria prison and Corrections says the situation at the facility remains "incredibly volatile".
Incident controller Jeanette Burns said there were tensions within the group of 16 prisoners at the "top jail" who had access to weapons and might have taken drugs from the dispensary.
"I appreciate that this event is significantly distressing for the family and friends of the prisoners involved," Burns said.
"We have no information to suggest that any of them are hurt."
They continued to urge the men to surrender, she said.
"We do not want the men, our staff or other emergency services staff to be harmed."
Burns said anyone who was not calling for the men to immediately peacefully surrender was putting the safety of prisoners, staff and emergency services at risk.
The prisoners have continued to light fires within the facility overnight, make threats toward staff and police and throw debris at them from the roof of the buildings, she said.
"We are concerned about the structural integrity of the burned buildings and the potential for them to collapse, and the toxicity of burned building materials," she said.
"Alongside this we know that there are tensions between members of the group, they have access to weapons and they may have taken drugs from the dispensary."
The situation remained "incredibly volatile" and options for intervention were limited because of the dangers present.
"Despite this, we are continuing to work closely with police to ensure that every opportunity to resolve the incident with the intention of minimising harm to anyone is considered and acted on.
"We have a duty of care to these men, and it is likely that they will remain in our custody for a number of years to come.
"Their point has been made. We are currently building a new facility to replace the existing top jail facility, which will be completed in 2022."
The group have been evading capture on the jail's roof after a riot that involved lighting damaging fires in the prison yard on Tuesday afternoon.
Corrections previously said while the damage to the top jail would need to be assessed, it was unlikely prisoners would be accommodated there again.
Meanwhile, desperate family members on the outside have urged them to give up but warn their loved ones are "willing to die" if their demands for basic needs are not met.
One relative told RNZ today that their cousin who is protesting doesn't care if he lives or dies, because he's standing up for his rights.
"He was agitated, he was hungry, he was thirsty ... but he said he'd stick it out ... at least he knows he's standing up for his rights and the rights of others who are going to be incarcerated in this prison."
The woman told RNZ her cousin was only on remand for non-payment of fines and had a 6-month-old baby at home.
Prisoner payphones, and all other phones at the prison, are currently not functioning.
Corrections says it appreciates this will be worrying and inconvenient for prisoners and their family and friends and is working to resolve this urgently.
It says it can provide assurance that all prisoners in other units are safe and well in the prison.