Vic man kept 'volatile bomb' in bedroom

A Victorian man allegedly behaved as if he was "playing with a firecracker" but instead it was an unstable, high-powered bomb.

He also stored it in a bedroom of his suburban Geelong home.

Police acted on a tip-off and raided the man's house, in Whittington, early on Thursday.

When he showed them the device - a gel-like commercial explosive stored in a cylinder along with detonators - they evacuated nearby houses and called in the bomb squad.

"The man had an explosive and other materials ... which he thought he would hide all together," Sergeant Shane Connolly told AAP.

"He put detonators in with (the explosive) and that made a volatile bomb."

The street was in lockdown from about 8am until noon as a robot inspected and took apart the device.

Sgt Connolly said the man did not appear to have a malicious motive.

"In his mind, I think he thought he was playing with a firecracker," Sgt Connolly said.

"The reality was a hell of a lot bigger and, by his own actions, he has created a very unsafe area."

The 45-year-old man has been charged with numerous explosives possession-related offences.