About 12 people have died, and more than 50 are still missing after heavy rain caused a ravine to collapse onto a river in the southwest Democratic Republic of Congo.

 According to a local official and a civil society leader, the landslide occurred around midday on Saturday in Dibaya Lubwe commune in Kwilu province.

It sent a cascade of clay and debris down to the banks of the Kasai River, where a boat was docking and people were washing clothes.

Confirming the incident, Interim provincial governor Felicien Kiway said 12 bodies had been pulled from the rubble so far, including nine women, three men, and a baby.

"Around 50 people are missing but we are continuing to search through the clay," he said.

Further, he said that chances of finding survivors were thin as the incident had occurred 12 hours prior.

Arsene Kasiama, the coordinator of a local civil society group, said the landslide also hit people shopping at a market.

He gave a death toll of 11, with seven seriously injured survivors and more than 60 people still missing.