At least five people have been killed after the White Island volcano erupted in New Zealand.

Tourists were seen walking inside the crater of the volcano just moments before the eruption, with the number of fatalities expected to rise.

Local authorities said 23 people had been rescued.

However, they warned conditions were hampering the operation, with the New Zealand military stepping in to help police.

Known as Whakaari, the volcano is one of the most active in the country.

It is also a tourist attraction with frequent day tours and scenic flights available.

Deputy police commissioner, John Tims, said due to the risks, emergency services were not able to access the island.

It is currently unclear how many people remain trapped, but Tims added “both New Zealand and overseas tourists” were believed to be involved.

Police had previously said they thought fewer than 50 people were on the island.

Image: Guo Lei/Xinhua News Agency/PA Images