The boat, carrying around 250 passengers traveling from a wedding, capsized in the early hours of Monday in north-central Kwara State.
"One part of the boat by the engine side collapsed where water penetrated the boat, which ultimately led to the boat capsizing," Kwara police spokesman Okasanmi Ajayi said in a statement.
"All efforts to draw the attention of the villagers hosting the wedding ceremony for assistance by the persons in the boat proved abortive, leading to the deaths of about one hundred and six people."
On Tuesday, 103 people had been reported dead. More than half of the victims were from one village.
President Bola Ahmed Tinubu offered his condolences to the families of the victims on Wednesday, and said his government would look to improve inland water transport safety.
"I am deeply saddened by the news of the tragic boat accident that claimed the lives of our people in Kwara State. That the victims were guests at a wedding ceremony made the unfortunate accident more painful," he said in a statement.
River travel is a popular form of transport in Nigeria, but accidents are also unfortunately common.
Last month, 15 children drowned and two dozen others went missing after their overloaded boat capsized in northwest Sokoto State as they collected firewood.
Almost a year earlier, another 29 children from a nearby village drowned in the same river as they were also on a trip to gather firewood for their families.
During huge flooding in the rainy season last December, at least 76 people drowned when their boat sank in a swollen river in southeastern Anambra State.
Nigeria's waterways authority has tried in the past to prohibit night-time sailing on rivers to prevent accidents and says overloading vessels is a crime, but crews often break regulations.
Forum