Detectives from Bendigo Crime Investigation Unit are appealing for witnesses after a man tried to hold up a 24 hour convenience store early this morning.

Police have been told the man, wearing a balaclava, has entered the Williamson Street store around 2.25am today.

He has thrown a white plastic shopping bag on the counter and then produced a firearm from his waistband and demanded money from the attendant.

When the demands were refused, the offender walked out of the store and was seen getting in to the passenger side of a silver Commodore sedan in Hopper Street.

The vehicle was then driven away.

The offender is described as Caucasian, approximately 170cm tall, with a thin build. He was wearing a black T shirt with a Jagermeister logo and blue tracksuit pants.