|Entire houses have been washed away by the flood water.|
The Matanikau and Lungga rivers burst their banks late on Thursday, washing away homes and bridges, and submerging large areas of the capital, Honiara.
The national disaster body said six people had died, but a government spokesman told ABC News that 16 bodies had been recovered.
Flood water is continuing to build as the rain continues.
Pictures showed debris washed on to the shore and houses washed into the river.
More people were reported missing and the death toll was expected to rise, aid workers said. Cyclone threat
Disaster officials said several evacuation centres had been set up.
The director of the National Disaster Management Office (NDMO), Loti Yates, told the BBC that people had lost their lives because they had failed to heed earlier government warnings to move away from river banks.
Some roads leading into the city, located on the main island of Guadalcanal, were reportedly closed.
The UN Office for the Co-ordination of Humanitarian Affairs said the floods had followed days of heavy rain, which was still falling.
“The depression is threatening to turn into a category one cyclone in the coming hours and days,” regional director Sune Gudnitz told the AFP news agency.
“The water has not subsided and flood waters are continuing to build.”
|Residents have been warned to go to higher ground and stay indoors|
|Many main roads in Guadalcanal have been shut due to high water levels|
|The flooding followed days of heavy rain in the area|
Solomons Prime Minister Gordon Darcy Lilo said the government would declare a state of emergency, local media report.
Loti Yates told the Solomon Islands Broadcasting Corporation that the flash floods were the worst he had seen.
“There is so much heavy rain around the area that creates massive flash foods,” Mr Yates said, adding that malfunctioning drainage systems were contributing to the floods.
The NDMO has warned residents to go to higher grounds or stay indoors, the Solomon Times reports.
Australia has pledged at least A$50,000 (£27,900; $46,200) in funds to support flood relief efforts.
New Zealand has given an initial contribution of NZ$300,000 (£154,500; $256,200). New Zealand Foreign Minister Murray McCully told the New Zealand Herald that infrastructure and homes had been damaged. – BBC.