An erupting volcano has forced 6,000 people to flee their homes on an island in the Pacific nation of Vanuatu.

The Manaro volcano on Ambae island has been active since 2005 but recent activity has raised fears of a major eruption.

National Disaster Management Office Director Shadrack Welegtabit says Vanuatu plans to declare an emergency on the island after the volcano's activity level was raised to level four for the first time over the weekend.

Authorities told villagers near the Manaro volcano to expect volcanic gas, airborne rocks and ash. They say acid rain could damage crops.

Welegtabit says about 10,000 people live on the island and those living in the north and south are most vulnerable. They have moved into schools and community halls to the east and west.