Tanna's homeless desperate for water

More than 100 people made homeless by Cyclone Pam are still without food and water in an evacuation centre in Vanuatu.

Locals have been sheltering in a former co-op store on the eastern side of the southern island of Tanna since Friday morning, when Cyclone Pam roared across the group.

They include families, elderly people and baby Angelina Watskall, who was born more than a week ago.

One person, who had been living there, died on Wednesday because they could not be treated for their illness.

Tanna authorities have found it extremely difficult to direct aid without computers, the internet, other communications or power.

Moses Lamaw, 65, says evacuees have been collecting water from a nearby creek and eating fruit found lying on the ground.

"We need water badly - that's our number one big problem," he told AAP.

Tanna authorities have been urging people to boil water before drinking it and warning them of the dangers of eating rotten fruit, but without any firewood, pots or food locals are growing increasingly desperate.

Another major concern is the risk of disease as Tanna has no working medical facilities and medicines is scarce.

So far 11 people have been confirmed dead in Vanuatu after category five Cyclone Pam struck on March 13.