A recovery mission to retrieve the eight bodies on White Island is yet to go ahead as experts continue to minitor activity on the island.
Police Acting Assistant Commissioner Bruce Bird told media today he was conscious families wanted loved ones bodies returned as soon as possible, but that they wouldn't put any other lives at risk to do so.
His comments come as GeoNet recorded this morning a significantly increased volcanic tremor at Whakaari/White Island - indicating that volcanic gas pressures remain high. The Volcanic Alert Level remains at level 3.
GeoNet said the situation remains highly uncertain as to future activity with eruptions in the next 24 hours still likely to occur.
"In terms of the operation to recover the bodies, we will make decisions based on all of the facts we have got and we will not be moving until the situation is safe for us to operate in," Mr Bird said.
A group of scientists and experts who have met in Wellington have been monitoring data from the island and other sources every two to three hours, he said.
"We are working out the plan of how we will actually go about and do that. The reason we've not got that completely identified yet is we've got to be certain of the environmental situation out there on the island.
"Safety for our staff is a huge priority for us and we've got to get this right. We've got scientific information that's at our disposal and we need to assess that information before we make a decision."
Following the two explosions, Mr Bird said a local helicopter pilot spent time on the island. He said, as well with other witness statements, police were satisfied there were no people alive on the island.
"We cannot put other people in jeopardy to go out there until we're absolutely certain that the island is actually safe."
Mr Bird said the bodies of those confirmed dead have been flown to Auckland for the post mortem process. He said the pathologists based in Auckland would ensure the process was smooth, accurate and as swift as possible.
Five people were confirmed dead on the day of the incident, and another person died at Auckland's Middlemore Hospital last night.
Of the 47 people who were on the island when it erupted at 2.11pm on Monday, 30 are still in hospitals throughout the country, three have been discharged and eight are unaccounted for, presumed dead on the island. Of those still in hospital, 25 are in a critical condition.
Mr Bird said the identities of those confirmed dead or missing are yet to be officially released until formal identification is completed.
"We understand there is international interest. While we are working through this process we are unable to confirm how many of the deceased are from each country."
He added police would release names along with nationalites as their identities are confirmed through formal identification.
Chief Coroner Judge Deborah Marshall told media today she had declared a mass fatality incident which means several agencies were working together to resolve the tragedy.
"We will be using the nationally recognised Interpol standards for victim identification and that includes our fellow stakeholders, pathologists, the police, ESR scientists, forensic odontologists and others, and they have all gathered together for this purpose."
The first stage of identifying bodies would be collecting ante-mortem data, she said, which includes getting information about what the deceased was wearing, including jewellery, and identifying any scars and tattoos they may have.
Ms Marshall said the post mortem process had already started in Auckland. Information gathered together will be presented to the Coroner who will decide if it is significant enough to identify a person involved.
She said most bodies will be taken to the Auckland mortuary, but if there are any further deaths in hospital it may not be necessary if they are already identified and have hospital records.
Ms Marshall also assured it was "business as usual for Coroners", so any deaths not related to the incident at White Island will receive the same level of treatment.