The aid agency has registered more than 2500 families for aid distribution on the neighbouring islands of Santo, Maewo and Pentecost, from more than 11,000 people evacuated from the island.
The state of emergency on Ambae has been extended until next week and the government said no one may return until it is lifted.
Red Cross spokesperson Shirley Johnson said a staggered repatriation would start with Ambae residents who live furthest from the volcano.
She said they were eager to return.