Police will hand over the search for the last victims of the White Island explosion to local experts - but insist "we haven't given up".
The two remaining bodies missing since the White Island eruption are likely to have been washed out to sea, police say.
Tour guide Hayden Marshall-Inman, 40, and Australian tourist Winona Langford, 17, are the two people who have not been found since the volcano erupted on Monday, December 9.
The police dive squad has searched for them without success.
Deputy Commissioner John Tims said there was no guarantee the bodies of those missing will be found.
It was the considered view of experts that their bodies were washed out to sea after a "significant weather event" the night of the island's explosion, Tims said.
"Police recognise the immense pain this must cause their families."
"We have always had an expectation of ourselves and others that all bodies would be recovered so it's both disappointing and frustrating to be in this position," he said.
As the chances of finding the bodies of Langford and Marshall-Inman diminishes, the recovery operation will also change.
The recovery operation will not be local-led, headed by District Commander Superintendent Andy McGregor, Tims said.
The Eagle helicopter, Deodar vessel and other police resources are to remain in Whakatāne for several days, but beyond that, the effort will continue at a local level,
This evening's announcement followed a police outline today of the overall response to date using maps and data.
That information was then presented to the Hayden Marshall-Inman's family.
Tims said that if police and other agencies were again required in the recovery efforts, they would respond.
Police Deputy Commissioner Mike Clement said this afternoon the two bodies had been near a stream that ran off the island. There was a significant weather event on the night the volcano erupted and police believe the bodies have not been on the island since December 10.
A 1.5m wave of water and sediment is believed to have come down the stream on Whakaari and washed the two bodies away, police say.
The stream was searched three times, and aerial imagery also confirmed the two bodies were no longer there.
It is Clement's "strong view" that the bodies of Langford and Marshall-Inman were washed out to sea.
"What we know is on the 11th of December there was a body of a male off the coast in the bay adjacent to the jetty and we believe that person to be Hayden Inman" - although there was not a visual identification.
Clement has this afternoon been with Marshall-Inman's extended family, walking them through the police belief that his body is in the sea, and they have accepted that view.
On the day Marshall-Inman's body was seen in the water, the Deodar police boat could not get close enough to recover the body.
"Despite our best efforts, we weren't able to get [the body] before it went down again," Clement said. "They got very close to the body ... within metres."
The recovery team were "deeply disappointed" they had not been able to recover him for his family, Clement said.
The Langford family are in Australia focusing on Winona's brother Jesse Langford, 19, who survived and is in hospital in Australia.
Since December 9, there has been no sighting of Winona Langford's body.
Clement is briefing his counterpart in Australia who will relay that information to her extended family.
The 17-year-old's parents Kristine Langford, 45, and Anthony Langford, 51, also died in the Whakaari tragedy. Jesse Langford is the only member of his family who survived the eruption and remains in a coma in Sydney's Royal North Shore hospital.
Clement said the sea had been searched near the jetty, where the stream enters the sea, and further out into the bay.
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The navy's sonar have been used to search the seabed and where there have been images of interest, divers have looked closer.
The dive squad has been working in difficult conditions with swell and low visibility. In areas about 200-300m from the shore, the water is around 50m deep. It is also acidic due to the eruption so divers have been using additional protective equipment.
Police have also been doing intense aerial searches of an area 5.5 to 6 nautical miles off the island.
On advice of locals including pilots, fishers and tour operators, police have also directed their search toward East Cape which is where the tide would have taken the bodies.
Clement said police were "deeply sorry" that they had not found the bodies. "We haven't given up ... but we have reached a phase where we are literally in the hands of the sea."
Searches will resume at first light tomorrow if possible, with weather meant to improve from tonight. The poor weather, which had hampered the recovery efforts, had given the team a chance to recharge and check their equipment, Clement said.
The air force will continue searching the area east of White Island.
Anyone wanting to undertake a private search of the East Cape is not discouraged from doing so.
Clement earlier told RNZ the chance of finding Langford and Marshall-Inman's bodies was slim.
Regional police will take over the operation in a few days.
Meanwhile Karla Mathews' siblings Nicola Mathews and Kirk Mathews Bowden have released a statement following the Australian being confirmed among the dead.
"Our family is absolutely heartbroken and our big sister will be incredibly missed.
"We have an enormous sense of relief that she has finally been found."
Mathews was travelling on the Ovation of the Seas with her partner Richard Elzer and friend Jason Griffiths, both of whom also died in the eruption.
GNS Science said the situation on White Island remains quite uncertain. The volcano's alert level remains at Level 2, and there is a low (20-40 per cent) likelihood there would be another eruption within the next 24 hours.
"An explosive eruption from the main vent area remains possible and could still occur with no precursory activity, especially if there is a collapse of unstable material around one of the vents, or if the gas emission decreases, allowing groundwater to enter the vent. Sudden steam/gas eruptions from other active vents are also possible," GNS Science said.
The rāhui around the area is to remain in place, although it has been lifted in part to allow swimming and kayaking but the gathering of kaimoana is still prohibited.