Earlier concerns were expressed about the conditions displaced islanders were facing on Maewo, including shortages of food and water.
However the WASH co-ordinator, Malatu Paolo, said the water on Maewo is safe for drinking, cooking and washing purposes.
He said any more bottle water shipped to the island would only pollute the pristine environment.
Maewo Island is well known for its spectacular waterfalls as well as streams from the north to the south.
RNZ Pacific's correspondent said Maewo's indigenous population numbers approximately 3000, which is why the chiefs of the island welcomed the Ambaeans, saying they had sufficient land to accommodate them.