The UN in Vanuatu says 24 people have died and 3,300 are displaced after Cyclone Pam hit the Pacific archipelago early onSaturday.
The UN Disaster Assessment and Coordination team in the capital, Port Vila, said 37 evacuation centres had been set up, but communication with outer islands was still down.
President Baldwin Lonsdale said the storm had "wiped out" all development of recent years.
He called again for international aid.
Of those who died, 11 were from Tafea island, eight from the main island, Efate, and five from Tanna.
The evacuation centres were catering for the many people who had lost their homes, the UN said, adding that the response effort was for now focusing on the capital and Efate.
After aerial assessments of the damage caused by the storm, Shefa remained the only province declared an emergency, the UN said.
Aid began arriving in the storm-hit nation - one of the world's poorest - after flights to Port Vila resumed.
Tropical Cyclone Pam is slowly weakening as it travels towards New Zealand and poses no further threat to Vanuatu or the South Pacific, a report by the UN Office for the Coordination of Humanitarian Affairs (OCHA) says.