KINSHASA (Reuters) - At least 45 people were killed and another 100 were missing after a boat sank on a remote stretch of river in Democratic Republic of Congo, a local government official said on Friday.

"Forty-five bodies have been recovered so far. The 112 people missing are river fishermen," said Mathieu Bela, district commissioner for North Ubangi in the far north of Congo, on the border with Central African Republic.

Another 25 passengers survived the accident but Bela said local authorities had not received any help from either government due to the lack of information and inaccessibility.

"The accident happened on Tuesday night when the boat struck a rock in the dark. There are no signs or signals, which does nothing to help navigation," he said.

The boat sank on the Ubangi river, which forms part of the frontier between Congo and Central African Republic.

Congo is a vast mineral-rich nation but roads are almost non-existent outside the main towns so travel is often limited to airplanes and boats plying its huge network of rivers.

Accidents are frequent due to over-loading and lack of maintenance.

(Writing by David Lewis; Editing by Alistair Thomson and Jon Boyle)