The discovery was made on Monday in an uncompleted four-bedroom flat at Asunta Quarters, behind Baptist Primary School in the ancient city of Kabba, the News Agency of Nigeria reports.
A combined team of the State Security Service, police and soldiers, acting on an intelligence report, cordoned off the building at about 2 p.m.
They forced the iron doors open and with the aid of the Police Anti-Bomb Squad recovered the devices.
Other items recovered include NPK brand of feriliser and other chemicals that are basic raw materials in the manufacturing of explosives.
Also recovered are army camouflage cap, saw, cables wires, transistor radio, batteries of different sizes and video CD players, used for testing the devices, but no arrest has been made.
The Commander, Police Anti-Bomb Squad, Mr. Cletus Nzeji, said that all the recovered items would be taken to their laboratory for analysis.
He confirmed that the recovered five hand grenades were of high capacity and were capable of bringing down a three-storey building.
He said investigations would reveal whether the devices belonged to armed robbers or the Boko Haram sect, but promised that the owners would be tracked down.
Nzeji said that the building where the items were discovered would be demolished, while the owner of the building would also be identified.