Reconnaissance flights over White Island, or Whakaari, have not revealed any signs of life, police said. Five people are confirmed dead and at least 10 are unaccounted for.
Tourist Michael Schade posted multiple photos and videos of the erupting volcano as he left the island.
Police said they do not expect to find any more survivors after the White Island volcano unexpectedly erupted on Monday.
Five people are confirmed to have died after White Island, also known by its Maori name of Whakaari, erupted at 2:11 p.m. local time (8:11 p.m. ET on Sunday).
The five people confirmed as dead were among 23 people evacuated from the island after the eruption. The remaining 18 people all had injuries of some degree, including severe burns.
Police earlier said that at least 10 people were thought to still be on the privately owned island, which is about 30 miles off the east coast of New Zealand’s North Island and popular with tourists.
The view of White Island from New Zealand’s Bay of Plenty coastline after the volcano erupted.
Emergency services have been unable to get access to the island on the advice of volcano experts, who said the scene was too dangerous and unstable.
But reconnaissance flights over the island since the eruption have not revealed any signs of life.
“Police believe that anyone who could have been taken from the island alive was rescued at the time of the evacuation,” a police statement said.
“Based on the information we have, we do not believe there are any survivors on the island. Police is working urgently to confirm the exact number of those who have died, further to the five confirmed deceased already.”
“We know that there were a number of tourists on or around the island at the time, both New Zealanders and visitors from overseas,” Prime Minister Jacinda Ardern told an earlier press conference.
“I know there will be a huge amount of concern and anxiety for those who had loved ones on or around the island at the time. I can assure them that police are doing everything they can.”
Coastguard rescue boats are pictured alongside the marina near Whakatane, around 30 miles from White Island.
Videos and images posted online by tourists who left the island, shortly before the volcano erupted showed a huge plume of white ash in the sky.
Visitor Michael Schade said he and his family had been in the crater of the volcano just 30 minutes before it erupted.
Another video Schade posted shows what looks like a destroyed helicopter close to the shore of the island, as people waited to leave.
Last photos: here are the White Island Tour operators rescuing people, timestamp 14:24 (~12-14 minutes after eruption). Endless gratitude to that crew for stepping up as first responders. I took these and reporters welcome to use with attribution.
A webcam operated by New Zealand’s geological hazard agency GeoNet showed at least one group of tourists inside the crater shortly before it erupted. The camera later went dark.
John Tims, deputy commissioner of New Zealand police, told journalists at an earlier press conference that 10 people remained unaccounted for on the island but could not be more specific. The victims include a range of nationalities, Tims added. Police had earlier said around 50 people were on the island when the volcano erupted.
“Our thoughts are absolutely with the friends and family of those that are injured and those who have died,” he said.
Australian Prime Minister Scott Morrison tweeted to say that Australians had been “caught up in this terrible event.”
White Island or Whakaari is New Zealand’s most active cone volcano. It last experienced a short-lived eruption three years ago.