Scientists are warning airlines and tourists of the danger of ash and volcanic rocks erupting from Mt Yasur on Vanuatu's Tanna island.
Wellington's Volcanic Ash Advisory Centre has reported an ash cloud covering 100 nautical square miles and more than 1.8 kilometres high within the volcano's vicinity.
A geohazard technical advisor for the Vanuatu government, Sylvain Todman, says tourists are now banned from visiting the volcano and the government's assessing the impact for the ten villages nearby which are being affected by gas and ash spewing from its crater.
"We saw very large explosions and important explosions outside the crater rim. All these bombs could reach all the villages around the volcano. We have a new kind of activity with a lot of ash falls, very large ash plumes and very important gas."
New Caledonia's domestic airline has cancelled or delayed several flights to Mare and Lifou in the Loyalty Islands.
Air Vanuatu says none of its flights have been affected.