Residents have reported power cuts amid further eruptions at a volcano on the Caribbean island of St Vincent, with loud rumbling, lightning and heavy ashfall also observed.

The eruption of La Soufriere on Friday forced many residents to evacuate their homes, although some remained in place.

The rumbling was heard in the capital of Kingstown, about 32 kilometres to the south, on Sunday.

“I’m just here wondering when it’s going to calm down,” resident Kalique Sutherland said.

Lava has begun to flow from the volcano, according to Professor Richard Robertson, the lead scientist at the University of the West Indies Seismic Research Centre.

“It’s likely that at some point it would quiet down and hopefully we would have a break so that we could recover a little bit more, but don’t be surprised if after the break it picks up like this again,” Professor Robertson said.

Elford Lewis, a 56-year-old farmer who evacuated his home on Sunday morning (local time), said the ongoing eruption was worse than the last big one in 1979.

“This one is more serious,” said Mr Lewis, who witnessed the big eruption decades ago.

An eruption of the 1220-metre volcano in 1902 killed roughly 1600 people.

About 16,000 people have had to flee their ash-covered communities with as many belongings as they could stuff into suitcases and backpacks.

However, there have been no reports of anyone being killed or injured by the initial blast or those that followed.

Ralph Gonsalves, the prime minister of the 32 islands that make up the country of St Vincent and the Grenadines, has said people should remain calm and keep trying to protect themselves from the coronavirus.

He said officials were trying to figure out the best way to collect and dispose of the ash, which covered an airport runway near Kingstown, and fell as far away as Barbados, about 190 kilometres to the east.

About 3200 people took refuge at 78 government-run shelters, and four empty cruise ships stood ready to take other evacuees to nearby islands, with a group of more than 130 already taken to St Lucia.

Those staying at the shelters were tested for COVID-19, with anyone testing positive being taken to an isolation centre.

Nearby nations, including Antigua and Grenada, also offered to take in evacuees.