Māori Party co-leader Rawiri Waititi has been granted access inside Waikeria Prison, after calls from inmates to help end the four-day standoff.
Sixteen inmates remain holed up in what’s known as the 'top jail', a unit built in 1911 the group have destroyed by lighting fires, which still burn.
Late Thursday night Corrections confirmed one inmate had surrendered, but 16 men remain "non-compliant".
Inmates earlier said Waititi was the only person they wanted to negotiate with. Corrections initially declined his offer.
The inmates have been protesting the allegedly inhumane treatment they've been subjected to.
Waititi says "a number of prisoners" contacted him directly to discuss their concerns.
"I've heard their call and I am making my way to Waikeria to meet with them, to listen, to support their call for justice and work towards a solution," he said.
"They deserve the right to be treated humanely, with fresh water, food and clean clothing and they deserve to have someone advocating for them."
Earlier on Thursday, the 17 inmates on the roof took turns to keep watch in the 24C heat while the others slept.
One wore a T-shirt and others paced as guards below traversed the remains from the fires, while at the gate a prison officer's daughter waited.
"You just don't know whether it's going to turn violent," she told Newshub. "You're just hoping that they're going to give in. You just don't know what they're thinking."
One-third of Waikeria Prison is now destroyed following the protest.
The inmates' gripe was the conditions they endure inside the oldest unit, built in 1911, which they've now destroyed. It'll be 2022 before the replacement unit that is under construction is finished.
Before Waititi announced his plans to speak to the prisoners, he told Newshub earlier on Thursday why he would be keen to do so.
"We've just got to make sure that we move our egos out of the way," Waititi said.
"If it means that the only person they will talk to is myself, I am willing to go in there and talk to them."
He believes if he speaks to the inmates, "it could result amicably".
"This is what needs to happen because the current system is broken and it continues to feast on the dysfunction it creates and funds itself."
Up until Thursday morning, one source told Newshub the 17 inmates on the roof hadn't had food or water since Tuesday. They also said prisoners are "squeezing water out of an old fire hose but the water is brown" and have resorted to filtering their urine through tissues.
Corrections wouldn't front for Newshub on Thursday, but on Wednesday declined Waititi's offer.
"I would leave that process to our negotiation teams to manage," Corrections chief executive Jeremy Lightfoot said.
Corrections confirmed in a statement on Thursday evening that the prisoners agreed overnight to surrender if they were able to meet with kaumatua.
"An operation involving support from our Advanced Control and Restraint staff was planned to enable this to happen safely, however did not resolve the situation," a Corrections spokesperson said.
Neither staff nor prisoners have been injured so far in the protest, and Fire and Emergency, police, and St John remain at the prison, they say.
Around 200 inmates were moved to other prison sites on Wednesday due to concerns for their safety and wellbeing, and these people are being given support to contact their family.
"Mental health support is also being made available to them as a number have found the events of the last 48 hours traumatic," the spokesperson said.
"We will be looking to prioritise their re-engagement with education, employment and rehabilitation activities that have been interrupted as a result of the incident."