At least 20 people including a baby died when an overcrowded boat sank on a river in the western Democratic Republic of Congo the weekend, local authorities said on Tuesday.

The disaster struck a motorized wooden vessel overnight from Saturday to Sunday on the Lukenie River in the Kutu area of Mai-Ndombe province.

The "overloaded" boat carrying about 300 people and goods sank after it hit some wood as it was heading for the town of Nioki, Kutu district administrator Jacques Nzenza told AFP.

"Yesterday we found four bodies and today 16 more were retrieved, including a nine-month-old baby," he said, adding that the search was continuing.

River and lake voyages are common in the vast central African country, where passable roads are scarce.

"We are constantly reminding everyone that it is forbidden to sail at night because it is very dangerous," Nzenza said.

At least 25 people died in July when a boat on the Congo River sank in the eastern province of Maniema. About 100 died in 2019 in a wreck on Lake Kivu.