At least 49 people have died after a boat tipped over on the Congo River in the country's northwest, according to Congolese officials.

The boat was taking people from a village to the city of Mbandaka on Thursday but capsized, Tshuapa province’s vice governor, Richard Mboyo Iluka, said.

He said a team has been dispatched to investigate and determine the exact death toll.

Mr Mboyo Iluka said he did not know how many people were on the boat or how many may have survived, and a cause of the accident remains unknown.

But he added that the boat had been travelling by night and did not have lights..

The Congo River is the second longest in Africa, and, with a maximum depth of more than 220 metres, the world’s deepest.

In a country with few roads or railways, it is a vital trade route and the best way for many people to traverse the Democratic Republic of Congo (DRC).

Boats on the river are often overcrowded and accidents are common.

Forty-two villagers who were fleeing violence between an armed group and security forces drowned last month after their boat capsized on the Ubangi, a tributary of the Congo River.

The latest accident comes amid a growing Ebola crisis in the DRC, where the country's health ministry have confirmed 31 cases of the virus, including nine deaths, this month.

Mbandaka, the boat’s intended destination, is home to a million people and was the first city in the DRC with a confirmed Ebola case in the most recent outbreak.

There are fears in the country’s capital, Kinshasha, downstream from Mbandaka, that the busy river may bring the virus to the capital city.

The DRC is also in the midst of an ongoing inter-ethnic conflict, which has seen at least 1.3 million people, including more than 800,000 children, internally displaced, according to a UNICEF report released in January.