RNZ reports conditions are becoming critical in both north Pentecost and south Maewo islands, which are very close to Ambae.
Mt Manaro on Ambae has been erupting intermittently for ten months but an escalation in ash fall over the past two weeks has prompted the government to announce a mandatory evacuation of the island.
Meanwhile neighbouring Maewo and Pentecost are being affected and on north Pentecost the ash has forced people to use torches and lanterns in the middle of the day.
There are reports of an urgent need water while food crops have been badly affected.
Garden crops above the ground have been covered with ash and cannot be eaten.