The UN Children's Fund ( UNICEF) and the World Health Organization (WHO) are also supporting an emergency government-led vaccination drive to protect children affected by cyclone Pam in Vanuatu, a UN spokesman told reporters here Wednesday.

UN agencies also continue aid to the island country after Cyclone Pam attack left 11 people dead, Farhan Haq, the deputy UN spokesman, said at a daily news briefing here.

"There are fears of a serious measles outbreak in the country, which already has very low rates of routine immunization and suffered an outbreak of measles, a potentially deadly disease, earlier this month," Haq said. "Six teams have been deployed in the capital, with six additional teams expected to be trained to begin vaccinations by the end of the week."

"More than 3,000 people have sought shelter in 26 evacuation centers but people are beginning to return to their homes," Haq said.

"Assessments missions to some of Vanuatu's worse-hit provinces have found that food, water, medical supplies, shelter and hygiene kits are urgently needed," he said. "Communication within and between the country's islands, as well as access to affected areas, is the greatest challenge to the humanitarian operation."

Nearly half of the 30,000 houses in the worst-affected parts of the country have been damaged by the cyclone, he said.

"Aid agencies continue to support the government providing help, with UNICEF having airlifted kits to cover 50,000 patients, while shelter kits and household items are being dispatched in the coming days," he added.

According to the World Meteorological Organization (WMO), Cyclone Pam, which also impacted the Solomon Islands, Kiribati and Tuvalu, had been one of the most powerful cyclones to make landfall, with winds having been estimated to have reached 250 km/ hour with gusts of 320 km/hour over the weekend.