Boating accidents are common in Congo, where old, wooden vessels are the main form of transport between villages and are often loaded far beyond capacity.
The boat was carrying as many as 100 passengers when it sank on along the Fimi River in western Mai-Ndombe province, the local official said. The victims included 15 women, five men and two children.
An overcrowded boat capsized as it made its way along the Fimi River. (AP PHOTO)
"Until we have safer, metallic boats, we will continue to have shipwrecks. There are thousands of these wooden ones circulating on the waters of Mai-Ndombe," the provincial governor Lebon Nkoso Kevani told Reuters.
He added that a team of provincial officials had deployed to the area to investigate and that many passengers were believed to have escaped to shore after the disaster.
In October, at least 78 people drowned when a boat carrying 278 passengers capsized in Lake Kivu in eastern Democratic Republic of Congo.
Anicet Babanga, a senator for Mai-Ndombe province, told Reuters on Wednesday that around 30 people were confirmed to have survived the latest wreck.
A search was underway to establish the fate of the other passengers.