Police say another person has died following the eruption on Whakaari / White Island, bringing the official toll to 15. The person was earlier being treated at Waikato Hospital.
The devastating disaster on Monday led more than 30 people to be admitted to hospitals across the nation, with medical professionals working around the clock in an attempt to save their lives.
Some suffered burns to more than 80 percent of their body, with some also having internal injuries due to the gases and chemicals inhaled on the island in the eruption's aftermath.
"These people all have really serious burns. Many of them remain in very critical condition in our intensive care units," Counties Manukau Health chief medical officer Dr Peter Watson told Newshub.
"They are going backwards and forwards to theatre to have more operations from the burns surgeons. But they are all very unwell.
"This is going to be a long road ahead for them. They will have times where they get better. But there might be times where they become more unwell. It fluctuates over time."
As of Saturday night, 14 people remain in New Zealand burns units - two in Christchurch, two in Hutt Valley, two in Waikato and eight at the National Burns Unit at Auckland's Middlemore Hospital. Three people have been discharged while 13 have already been repatriated to Australian hospitals.
Meanwhile, officials working on the mission to recover the remaining two bodies from the island are hoping to head back on Sunday.
Six bodies were removed on Friday during a mission carried out the elite SAS unit E Squadron.
However two remain missing. One of those is understood to be in the ocean and is being searched for by dive squads, while the second is unaccounted for.
"We're working towards a plan tomorrow," police deputy commissioner Mike Clements said in a Newshub interview.
"We have got to go through the same process that we went through the other day. I know it seems long and complicated because it is.
"We have had all of the agencies and the scientists locked away in the room… they will be doing exactly the same as they did the other day, presenting a plan to me and I, in turn, will discuss that with the Commissioner and Deputy Commissioner Tims later on this evening."
On Saturday, Prime Minister Jacinda Ardern announced that New Zealand will hold a minute's silence at 2:11pm on Monday, December 16, to remember those impacted by the eruption.
"Wherever you are in New Zealand, or around the world, this is a moment we can stand alongside those who have lost loved ones in this extraordinary tragedy," she said.
"Together we can express our sorrow for those who have died and been hurt, and our support for their grieving families and friends."
