WELLINGTON: Several people were injured and several others unaccounted for when New Zealand's White Island volcano erupted suddenly on Monday (Dec 9).
Prime Minister Jacinda Ardern said the volcanic island - also known as Whakaari - off New Zealand's north coast had erupted while groups of tourists were visiting.
At a news conference, Ardern said the authorities believed there were 100 people "on or around the island"
"A number of people are reportedly injured and are now being transported to shore," she added. "It does appear to be a very significant issue ... particularly the scale of people affected, at this stage."
However, New Zealand police later said they believed there to have been fewer than 50 people in the area at the time of the eruption.
"While it was initially believed there were approximately 100 people on or near the island at the time of the eruption, we now believe there were fewer than 50.
"Some of those people have been transported to shore, however a number believed to be on the island are currently accounted for," said the police in a Facebook post, adding that at least one of those transported to shore was "critically injured".
The authorities said they were working with the National Emergency Management Agency to coordinate a search-and-rescue operation. A no-fly zone has been established, they added.
The island is about 50km from North Island in the picturesque Bay of Plenty, and is popular with adventurous tourists willing to don hard hats and gas masks.
The White Island volcano is one of New Zealand's most active volcanoes.
According to the national Met Service, the eruption was visible on satellite images.
Whakatane mayor Judy Turner said "there have been people injured" and rescue missions were under way.
"I don't know how many or the state of their injuries but emergency services are currently frantically trying to get these people back from the island to hospital for treatment," she said.
She added that there seems to be no danger for the people in the coastal areas, farther from the volcano.
St John Ambulance said there were up to 20 people believed injured but medical teams were still en route.
There were particular fears for a group of visitors seen walking on the crater floor moments before the eruption occurred.
Cameras providing a live feed from the volcano showed more than half a dozen people walking inside the rim at 2.10pm local time (9.10am Singapore time), before images went dark when the eruption occurred minutes later.
A report by the NZ Herald said many of those visiting White Island on Monday were from the cruise ship Ovation of the Seas.
Port of Tauranga company chief executive Mark Cairns was quoted as saying that he understood the majority of those injured in the eruption are from the ship.
New Zealand's national emergency crisis centre has been activated.
The volcanic eruption made the area immediately around the island hazardous, the National Emergency Management Agency said in an emailed statement.
The agency described the eruption as "moderate", although a thick plume of white ash could be seen for miles around.
Several helicopters and aircraft could be seen in the area.
The "short-lived eruption" threw an ash plume about 3,658m high, New Zealand's geoscience agency GNS Science said in a statement, but added there were no current signs of an escalation.
White Island is New Zealand's most active volcano cone and about 70 per cent of it is undersea, according to government agency GeoNet.
Around 10,000 people visit the volcano every year. It has erupted frequently over the last half-century, most recently in 2016.
In August of that year the New Zealand Defence Force airlifted a 2.4-tonne shipping container onto the island to serve as an emergency shelter in case of an eruption.