The Solomon Islands Government says at least 16 people have died in flash flooding that has left thousands homeless in the capital, Honiara.
Government spokesman George Herming has told the ABC search and rescue efforts are ongoing, but are hampered by heavy rain and the huge waves that are battering the coastline.
Mr Herming says 16 bodies were recovered on Friday morning and an unconfirmed number of people are still missing.
Oxfam Solomon Islands country director Katie Greenwood says the floods are causing unprecedented damage.
Ms Greenwood says there has been a significant loss of houses along Mataniko River, widespread infrastructure damage and reports of landslides and flooding on the western and eastern plains of Guadalcanal.
She says Honiara residents are sheltering in schools and at the international airport, but relief agencies and the government will have to find better longer-term solutions.
Ms Greenwood says the flash floods are one of the worst disasters ever to hit Solomon Islands.
"This is unprecedented, and I've seen earthquakes and tsunamis and other very bad flooding incidents. But this flash flooding is unlike anything that I've seen previously here in the country," she told Radio Australia.
Loti Yates, director of the National Disaster Management Office (NDMO), says the flooding is more widespread than initially expected.
Mr Yates says initial rescue efforts had focused on Honiara but overnight (Thursday) the NDMO received calls for help from outside the city.
"We were starting to receive phone calls also from outside of Honiara as far as the northern part right in the middle of the Guadalcanal Plains of people having to resort to climbing over roofs... to seek shelter from the flooding rivers around them," he said.
the floods are "the worst disaster the nation has seen."
There are lingering concerns that the storm will develop into a cyclone, which could cause more damage and further stall damage assessment.
The Pacific nation may have a reprieve, however, as latest forecast is for the low currently over Solomon Islands to move toward the west over the Coral Sea this weekend
Oxfam's Katie Greenwood says the organisation is ready to work with the Solomons' government to help with providing clean water, shelter and health services.
The agency will also distribute essential non-food items like tarpaulins and hygiene kits to families whose homes have been washed away.
World Vision says its emergency response team in Solomon Islands has been activated and is on standby for cyclone activity.
Emergency relief for flood-stricken Solomons
The Australian Government is providing an initial $50,000 in humanitarian emergency assistance for the deadly flooding.
The aid will go towards helping the Solomon Islands Government and local non-government organisations with logistics and emergency relief items.
Australia is also providing specialist assistance to the NDMO and will help the government to undertake an initial aerial surveillance of the damage.
The government of New Zealand is providing close to $300,000 dollars in emergency relief.
It says the money will be used for relief supplies and shelter for the thousands of people made homeless after heavy rain and flooding.
Meanwhile, Australia's Department of Foreign Affairs and Trade has warning of road closures and delays at Honiara's Henderson International Airport.
© ABC 2014
17:04 EST The Blue Mountains, west of Sydney, has been blanketed by large hailstones as a severe thunderstorm moves across the area.