Up to 25 people are feared to have died when a barge sank on the Congo River, authorities in DR Congo's northeastern province of Tshopo said on Tuesday.

"A barge which was leaving Kisangani for Basoko sank on Friday evening. The toll today is six bodies which have been recovered, 237 survivors and 19 missing," Tshopo's vice governor, Maurice Abibu Sakapela, told AFP.

"The public prosecutor has opened an inquiry. Some people have already been arrested," he said, blaming "overloading and the poor state of the vessel" for the accident.

Rivers and waterways are widely used for travel in the Democratic Republic of Congo in the absence of paved roads and railways.

But many vessels are old or poorly maintained and skippers may turn a blind eye to rules on lading and safety, despite requirements passed in April 2019 for all passengers to wear life jackets. 

In addition, relatively few people in the DRC, a country the size of western continental Europe, learn how to swim.