Abubakar Zakari Adamu told The Associated Press that the figure includes a canvassing of local hospitals in Kaduna.
Earlier reports stated that the explosion had occurred near the Ahmadu Bello Stadium in the city center.
Spokesman for the National Emergency Management Agency, NEMA, said the attack had injured several local Okada riders who were in the vicinity, when the explosives packed in an abandoned vehicle, detonated.
The injured victims were immediately rushed to local hospitals in the area for treatment.
According to reports, the explosion was close to a church where worshippers had gathered for the Easter celebration, but there was reportedly no damage to the church.