At least seven people have been killed and 30 remain missing in the floods triggered by torrential rains in the Solomon Islands, The New Zealand Herald reported Saturday.
The floods, from a slow-moving tropical depression, have also left more than 10,000 people homeless in the capital Honiara.
The homeless have been shifted to 16 evacuation centres in the city with 70,000 people. But aid workers fear outbreaks of diseases from polluted water.
"This is by far the worst flooding I have witnessed since heading this organisation - the scale and magnitude is overwhelming," National Disaster Management chief Loti Yates was quoted as saying.
Search and rescue efforts were being hampered by heavy rain and huge waves battering the coast.
"The death toll is likely to rise and there appears to be significant damage to homes and infrastructure," New Zealand Foreign Affairs Minster Murray McCully said as he announced an initial contribution of $300,000 to support an immediate response to the disaster.