A source said three persons died on the spot while four died on the way to the hospital.
Many others sustained varied degrees of injuries.
The two-storey building, which was still under construction at Ikenga Ndiagu village, Ogidi in Idemili North Local government Area of the state, trapped some workers when it collapsed.
The building which was at the second floor stage, collapsed at about 4:30p.m.
The copses of the victims were moved to the Iyi-Enu Mission Hospital Morgue, Ogidi, while those who sustained injuries were admitted at intensive care unit of the hospital.
As of the time of filing this report, rescue teams were still battling to rescue some workers believed to be trapped.
It was gathered that the owner of the building was helping the police with investigation into the incident.
He was said to have been inspecting work at the second floor of the building when it collapsed and was treated for minor injuries before finding himself in the police custody.
Efforts to reach the Divisional Police Officer at Ogidi, Hassan Musa (CSP), were not successful.