Twelve people have been killed in two separate boat accidents in Nigeria, officials said on Tuesday.

In the first incident on Monday, two people died and another went missing after a fishing boat taking mourners to a funeral capsized outside the commercial capital Lagos, a government safety agency said.

Four people were rescued. None of the seven people on board were wearing life jackets, it said.

In a separate incident on Monday, 10 wedding guests drowned when their boat capsized in the Jega district of the northwestern Kebbi state, an emergency official said.

The victims were heading to a wedding ceremony in a village on the other bank of the river, said Sani Dododo, head of Kebbi State Emergency Management Agency.

"The boat capsized due to turbulent waves in the river which is full from heavy rains. All 10 passengers in the boat drowned. Four bodies have been recovered and search for the remaining six is underway," he told AFP.

"It is a difficult operation because the bodies were swept by the currents," he added.

Boat accidents are common in Nigeria because of overloading, disregard of safety guidelines, lack of maintenance and bad weather.