Particularly affected are the central parts of the capital Kinshasa, where the main streets were under water for several hours.
OCHA said in a statement that authorities in Congo-Kinshasa stated on December 16 that at least 169 people had died in the floods and that around 30 people were being treated for injuries. At least 280 houses are said to have been destroyed by the masses of water.
The areas of Mont-Ngafula and Ngaliema in the western parts of the capital must have been particularly exposed to the floods. According to OCHA, 38,000 people in those areas are affected.
A three-day national mourning began in Congo-Kinshasa on Wednesday.
Around 15 million people are believed to live in the capital, although there is no confirmed population count. Kinshasa is located on the Congo River, which can flood. Even greater are the problems with poor drainage and housing built on loose foundations along the mountain slopes around the city.