Thirty-nine people are believed to have been killed in a weekend ferry disaster in northern Democratic Republic of Congo (DRC), local officials said on Tuesday.

The boat, overloaded with passengers and goods, sank during a storm on Saturday while crossing the Ubangui River, from the Congolese town of Libenge to the capital of Central African Republic (CAR), Bangui.

"Until now, only nine bodies have been found. Eight have already been buried in Libenge and another in CAR," governor of Congo's northwestern Equateur province Jose Malik told UN-sponsored Radio Okapi.

Rescue teams have given up hope of finding survivors and are now concentrating on recovering bodies, Bruno Bindamda, the provincial minister of health and humanitarian affairs, told Reuters.

"With the time that has now passed, we do not think that the others are alive," he said. "There were no survivors."

Such accidents are common in the DRC, a vast country the size of Western Europe centred on the Congo river basin, where boat travel is often the best option due to poor roads. Safety standards are almost never enforced and there are seldom accurate passenger lists.