UNICEF says two thirds of children in Vanuatu have been affected by Cyclone Pam and require immediate help.

It has revised its Cyclone Pam humanitarian appeal, saying 4.8 million US dollars is required to meet the immediate needs of children affected by the disaster across the Pacific.

UNICEF says the appeal is critically underfunded.

Its Pacific Representative Karen Allen says children, especially in the hardest-to-reach islands in Vanuatu, are in serious danger.

She says access to safe water remains critical, and there is a significant risk of disease because of flooding, poor sanitation and limited medical care.

Ms Allen says life-saving supplies are getting through but more funds are required to reach more children.

FOOD SHORT AS PRICES INCREASE

A volunteer doctor says many people in Port Vila are short on food as prices increase.

Richard Henderson has been volunteering in Vanuatu for the past 18 months and says although the main town is bustling with activity, many poor suburbs are struggling.

Dr Henderson has been visiting the poorer areas of Port Vila and says one mother has lost half her weight since he saw her 6 weeks ago.

He says they've got basic food but need proper nutritional fruit and vegetables.

Dr Henderson says one cabbage at the local supermarket is worth the equivalent of 30 New Zealand dollars.

HUNDREDS STILL IN EVACUATION CENTERS IN TUVALU

The Tuvalu government says it is trying to work out how to deal with hundreds of people still living in evacuation centres in Nui, which was entirely flooded during Cyclone Pam.

A spokeperson, Panapasi Nelesoni, says 70 families are living in school classrooms after being displaced by the storm.

He says the government is working on moving the families into community halls so that children can go back to school.

"Some of the halls were that badly damaged as well. So we are trying to repair those halls, to move the families that are currently accommodated in the classrooms to those community halls and at the same time try to work out a response to try to get them back to build their own houses."

Panapasi Nelesoni says after past cyclones, the government has provided some financial assistance to displaced people trying to rebuild their homes.

He was not able to say whether the government would do the same following Cyclone Pam.