The floods, which UN officials in Geneva said were the worst to hit Sierra Leone in 45 years, made roads around the eastern town of Kenema impassable for UN vehicles that have been taking the refugees over the border, journalists in the region said.

A spokeswoman for the United Nations High Commission for Refugees (UNHCR), Rachel Goldstein-Rodriguez, confirmed that the operation had been suspended but said she hoped it would re-start "quite soon" when the weather permitted.

Despite the bad weather, she said, the UN agency began the third phase of a one-month checking exercise Wednesday designed to determine the "actual physical presence of refugees" from Liberia in the five refugee camps in the east of Sierra Leone.

"The exercise will give a more accurate picture of how many refugees are in the various camps," Goldstein-Rodriguez said.

It "gives us the opportunity for better planning and budgeting for our partners, particularly the World Food Programme (WFP)."

On Tuesday, a spokeswoman for the UN's humanitarian affairs bureau in Geneva said that 10 days of heavy rain had caused the worst flooding in Sierra Leone since 1945, and there would certainly be casualties.

On Friday the west African country's Red Cross Society said the rain had caused at least one death and forced 15,000 people to flee their homes.