Fears for public hygiene have intensified as the floods also hit cemeteries, "contributing to the already alarming sanitary conditions with the widespread debris caused by the high wave action", President Litokwa Tomeing said.

The president said at least 600 people were forced to take refuge in government-designated shelters, churches, and with other family members.

Radio Australia interviewed the government's chief secretary, Casten Nemira, who said damage to outer islands remained unknown until communication with them could be restored.

"Over 200 plus houses were affected and some houses are completely damaged, also the cemeteries by the shore lines and erosions," he said.

"We hope to get a complete picture in the coming days as the reports are still coming in."

Vulnerable

Deborah Manase, deputy director of the Office of Environmental Planning and Policy Coordination, said damage had been caused despite the waves that crashed into the islands being "quite small" at about five feet.

"It shows that we're extremely vulnerable," the AFP news agency reported her as saying.

"If the tide had been two feet higher, it would have been much worse.

"At the global level, we're trying to explain that the smallest change in sea levels will have a big impact on our islands."