Ash erupting fom the Manaro volcano on Vanuatu's Ambae island has blocked out the sun and forced 1000 villagers from 362 households to voluntarily register for off-island evacuation.

Photo: Vanuatu Red Cross

Eyewitnesses said in the worst affected areas ash fall darkened the sky so much yesterday that vehicles picking villagers up around midday had to use their headlights.

Even the safe zones on East Ambae were no longer safe and victims were being relocated to Lolowai which is on the north eastern side of Ambae, they said.

The National Disaster Management Office told the Daily Post newspaper that the MV Tauraken was expected to transport people mainly from south Ambae to the nearby island of Maewo today.

Pictures of victims arriving in Lolowai show people covered in black ash and wearing masks.

Disaster authorities said once victims were taken by ship to Maewo they would receive up to six months of government assistance with food to allow them time to make gardens and grow their own food.

Meanwhile, Vanuatu's Geohazards Department has increased the exclusion zone around the volcano from 2km to 3km.

Last week the department raised the volcano's alert level from two to three on the five- level scale.

Analyst Melinda Aru said people should stay well away from the vent.

"We are strongly urging the local communities not to access, not to go to the caldera or to where the active vent is," she said.

"Some people are curious about going up and seeing for themselves about ash fall and the impact at the top."

No one could predict how long the ash fall would continue, Ms Aru said.