At least 40 people have drowned after a passenger boat capsized in western Democratic Republic of Congo, a week after at least 47 others died in a similar incident.

The wooden riverboat, known as a whaler, was carrying passengers and goods, when it capsized on the Lulonga river on Saturday night.

The incident happened near Boyeka village in the Equateur province.

The passengers, mostly traders, were returning from a local market crossing to Mbandaka, the province's capital.

The death toll could rise as more passengers are reported missing. More than 200 others survived, local media reported.

The accident comes 10 days after another boat capsized in the same province, killing dozens. An unknown number of people are still missing.

Boats are a common mode of transport in DR Congo because of a lack of roads.

However, boat accidents are frequent because of overloading, poor maintenance and overnight travel.

Many passengers also do not wear life jackets.