A volcano on Papua New Guinea's Kadovar island has erupted, sending plumes of steam and ash 800m into the air with experts warning seismic activity beneath the volcano means an eruption could be imminent.

Thousands of people have been evacuated from the surrounding islands near Papua New Guinea's north coast with resources being deployed to support the relief effort. Flights around the area have been cancelled and ships warned to stay at a distance from the island.

The Rabaul Volcanological Observatory reported several moderate explosions from Kadovar in the days prior, and reported that the ash clouds had drifted tens of kilometres southwards.

In addition, the prime minister also warned coastal communities to stay alert to the small possibility of tsunamis.