"The accident occurred around 7.45pm (1845 GMT) on Tuesday in (the neighbourhood of) Festac Town when a wooden boat with some 20 passengers capsized," Ibrahim Farinloye of the National Emergency Management Agency told AFP.
"We have recovered 13 bodies, including two children, from the water while six others have been rescued," he said, adding that the boat had a capacity of just 12 people.
According to the released information, the capsized passenger vessel was ferrying people within the Festac town neighbourhood, across a small river.
It's not the first accident with overloaded vessels, but the ship operators usually allow carrying so many people, in effort to maximise their profits on account of safety measures.
Water travelling was aggressively promoted by the local government of Lagos city, populated with 20 million people, attempting to reduce the heavy traffic, particularly the choking traffic between the business hubs on the islands and the the mainland of Lagos where most of the people live.
According to the report, there are only a few companies in the area, offering safe ferry services with well-maintained vessels. The other companies engaged in ferry servicing are motor-powered canoes run by unqualified pilots.