The roof of the church in Uyo, the capital of Akwa Ibom State, caved in during the ordination of Akan Weeks as a Bishop. Witnesses claim the church was still under construction and workers had rushed to complete it for the ordination.
According to the BBC, authorities had ordered construction to stop work many times but were ignored.
The Akwa Ibom Government has already called for the arrest of engineers and contractors involved.
There have also been conflicting reports about the casualty figures. Eyewitnesses claim at least 50 died, while authorities put the number at 26.
The Christian Association of Nigeria has, however, warned churches across the country, against worshiping in uncompleted buildings.