H for help in cyclone zone

Desperate villagers on an outlying cyclone-flattened Vanuatu island have marked out a "H" for help to attract the attention of planes flying over.

Oxfam country director in Port Vila Colin Collett van Rooyen said aid groups were using aerial surveillance to work out priority areas for help.

The focus was now shifting to remote parts of the Pacific nation.

Mr Collett van Rooyen told AAP on one remote island village had marked "H" - asking for help - in white stones to draw attention to passing planes.

He said emergency medical staff would heading to Tanna Island on Wednesday.

The island's hospital has been damaged.

Authorities will focus on getting fresh water, food and sanitation kits into villages on Erromango island.

So far 11 people are confirmed dead.