New Zealand police have contacted the families and loved ones of all 47 people who were on White Island during Monday's volcanic eruption, but face major challenges to fully identify bodies and injured survivors.
Twenty-four Australians were on a tour of White Island when an active volcano erupted on Monday.
Three Australians are believed to be dead while eight others are unaccounted for.
The other 13 Australians who were injured, including Marion and Nick London from Engadine, have been taken to hospitals across New Zealand.
It is understood Mrs London, 56, is in a critical condition with severe burns while Mr London, 58, has serious hand injuries.
The nature of the eruption on the island, also known as Whakaari, caused survivors to ingest ash and volcanic gases, resulting in horrific injuries.
"There are a number of people in hospital who cannot communicate because they have significant burns not only to skin but to internal organs," Police Minister Stuart Nash told Radio NZ.
"They cannot speak ... or communicate."
The natural disaster has killed six people, officials say, but another eight people are presumed dead after they were unable to escape White Island.
Police say their primary objective is to repatriate bodies from the island to the families but they are still waiting for a stable environment on Whakaari so the retrieval operation can go ahead.
There are 30 people scattered in hospitals across New Zealand who were sent to different treatment centres to utilise experts in different cities.
Chief Coroner Judge Deborah Marshall said six bodies have been flown to Auckland for post-mortem examinations, but "ante-mortem" data was also being examined.
"That is information about the person we believe to be deceased gathered before their death," she said.
"For example, what they were last wearing, what jewellery they might have, any scars or tattoos that might identify them.
"There will be people, we hope, at the scene of this tragedy, gathering evidence from there."
NZ Police Acting Assistant Commissioner Bruce Bird said he understands there is huge interest in the identification process and officials are working as fast as they can.
"As we confirm their identities we will release the names of those who have sadly died as soon as their formal identification process has been completed," he said.
Four coroners, including Judge Marshall, are in Auckland working on the tragedy.
Paramedic Rusty Clarke was on board a helicopter that flew to White Island on a rescue mission shortly after the eruption.
He likened the ashened landscape to that of a nuclear explosion.
"Looking down on it, I would have to describe it as Chernobyl," he told Radio NZ.
"It was just a complete, absolute whiteout of the area involved.
"It was quite a daunting experience seeing that initial landscape."
Police on Tuesday announced a criminal investigation would take place into the tragedy, only to walk that statement back an hour later.
Mr Nash described the initial announcement as "a slip of the tongue".
While NZ police have declined to make the nationalities of the dead public, Australian prime minister Scott Morrison said on Tuesday he understood up to three Australians had died in the disaster.