Cars, shops damaged in Vic graffiti spree

At least 18 cars and several shops have been damaged in a graffiti spree in Melbourne.

Police were called to Newport, south-west of Melbourne's CBD, in the early hours of Monday morning to discover the cars and stores vandalised.

Two teenage boys were seen in Challis Street, Newport, at about 3.45am (AEDT) attempting to steal a car but ran when the owner disrupted them, police said.

Officers believe the damage bill could exceed $50,000.

Police are continuing with the investigation.