Police added they still do not know an exact number of people involved in the incident, but both New Zealanders and international tourists are thought to be involved.
Police also said that it is too dangerous to search the island following the eruption, but a statement from St John Ambulance said it had now dispatched paramedics on helicopters, and was aiming to establish a triage unit on the island.
The New Zealand Defence Force has also been dispatched to the area to help emergency services.
"We can't be certain there won't be another eruption in the next 24 hours."
There will be questions asked as to why tourists were still able to visit the island after scientists recently noted an uptick in volcanic activity.
Royal Caribbean, whose cruise ship was visiting the mainland, had passengers on an excursion to the volcano.
A spokesperson for the company said: "We can confirm that a number of our guests were touring the island today. We do not have any additional details to share at this time."
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