A YouTube video has revealed the devastating extent of the flash flooding in the Solomon Islands, which has killed several people and left more than 10,000 people homeless.

The clip shows water flowing through a street, submerging houses and dragging large pieces of debris.

Heavy rain over the last few days caused the banks of the Matanikau and Lungga rivers to burst their banks, washing away homes and flooding vast areas of Honiara.

The national disaster body has confirmed the deaths of six people, yet a government spokesperson told ABC that 16 bodies had been recovered.

Officials have warned the death toll is set to rise, while Sky News has reported another 30 people are missing.

Local media have reported Prime Minister Gordon Darcy Lilo said the government would declare a state of emergency.

Disaster officials have said several evacuation centres had been set up and some roads leading into the city, on the main island of Guadalcanal, were reportedly closed.

Andrew Jeremijenko, a medical evacuation doctor from Brisbane, described the devastation to the Brisbane Times: "There is a widespread disaster developing here and we are sure there will be more than the bridge in Honiara out. There are trees across roads, flooded roads, and roads and bridges will be out across the main island of Guadalcanal."

He added that one of his Solomon Islands aid workers had lost her house and possibly several of her family members.

Jeremijenko said: ''One of my co-workers here - a Solomon Islander - had her family members washed out to sea. One has been confirmed as dead - her uncle - and one of the children was found and picked from the sea."

The Solomon Islands Broadcasting Corporation has warned the public to stay indoors to clear space for emergency workers. Loti Yates, the Director of the National Disaster Management Office told the corporation: "There is so much heavy rain around the area that creates massive flash floods."

The UN Office for the Co-ordination of Humanitarian Affairs said the flood had followed days of heavy rain, which was continuing to fall.

Sune Gudnitz, the regional director, told AFP that the depression could turn into a category one cyclone. He added: "The water has not subsided and flood waters are continuing to build."

Credit: Kim Letera