At least 12 people were killed and more than 50 are still missing after heavy rain caused a ravine to collapse onto a river in southwest Democratic Republic of Congo, a local official and a civil society leader said on Sunday.

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.

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

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

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

Poor urban planning and weak infrastructure across Congo make communities more vulnerable to extreme rainfall, which is becoming more intense and frequent in Africa due to warming temperatures, according to climate experts.

Reuters