International aid agencies ramped up appeals for cyclone-hit Vanuatu on Wednesday, warning that the powerful storm that affected more than two-thirds of the South Pacific island nation had wiped out crops and destroyed fishing fleets, raising the risk of hunger and disease.

Residents of the southern island of Tanna said food and basic supplies were running low while relief workers were still battling to reach many islands pummelled by Cyclone Pam's gusts of more than 300 kph (185 mph) on Friday and Saturday.

The United Nations said the official death toll was 11, but many officials anticipate that number will rise once they are able to more thoroughly inspect the outer islands of the scattered archipelago.