The building came down at about 4pm on Monday while construction workers were still on site.
Three persons are believed to be trapped under the rubble.
It is not yet clear what led to the collapse.
Rescue workers are trying to bring out the trapped victims, including an expatriate.
Top government officials in the state, led by the deputy governor, Dr. Pius Odubu, are supervising the rescue operation.
Central Hospital is a government hospital located in the serene centre of Benin, on Sapele road, few kilometers from the City Center.
Details and photos later.