New Zealand said on Tuesday that eight people were missing, presumed dead, a day after a volcano unexpectedly erupted off the coast of New Zealand's North Island, killing at least five people and injuring more than 30.

Prime Minister Jacinda Ardern told reporters in Whakatane, a town near the volcanic White Island tourist attraction, that aerial reconnaissance flights had shown no signs of life.

"It's now clear that there were two groups on the island — those who were able to be evacuated and those who were close to the eruption," Ardern told reporters.