Detective Sergeant Stephen Cole of the Kyneton police criminal investigation unit said the attempted armed robbery occurred just after 6pm last night.

He said the offender attended an address in Castlemaine and made demands of a man living there.

When the man refused to comply he was hit over the head with a sawn-off shotgun, Detective Sergeant Cole said.

The victim received minor cuts and abrasions to his head, he said.

Detective Sergeant Cole said the victim then pushed the armed robber out of the property and he left in an unknown vehicle.

He said the offender and victim appeared to know each other.

"It's not a random thing, the offender knows the victim," he said. 

He said police were in the process of trying to locate the offender and the shotgun. 

"Police are concerned to find the offender and the outstanding illegal firearm," Detective Sergeant Cole said. 

Anyone with information is urged to call Crimestoppers on 1800 333 000.