Vanuatu's Geohazards Department raised the official alert threat from level three to four as an eruption on Ambae island continues to intensify. The alert levels range from 0 to 5 - level five is a very large eruption.
The National Disaster Management Office along with a team from the Geohazards department left early Sunday morning for Ambae.
On Saturday, authorities were preparing to evacuate as many as 5,000 people from one side of the island to the other as the volcano belches ash across much of the island.
The volcano is one of the most active in the world, but its activity has picked up steadily in the past couple of weeks.
The director of the National Disaster Management Office, Shadrack Welegtabit, said the eruption was starting to look serious, and officials would look at a large-scale evacuation.
Mr Welegtabit said half of the island's population of about 10,000 would be moved from one side to the other.
"It will be a big operation. We are talking about roughly 5,000 people that we have to move. Once all the ground arrangements is done in terms of preparing evacuation centres and stuff then we are looking at moving people. That is going to happen very soon," he said.
The last significant eruption on Ambae was in 2005, when a similar evacuation was carried out. It was as long as three months before people could return to their villages.
Photo: Vanuatu Geohazards Department Ambae volcano