STONEFRUIT grower Steve Mammone thought he was on to a good thing last summer when a stranger offered to seal his entry and car park for half the going rate.

 It wasn't until after the bitumen and gravel were laid and he had handed over $40,000 that he realised he had been dudded.

Mr Mammone, who farms at Wood Wood, north of Swan Hill, was among several people in the region who were conned into paying good money for a bad job by itinerants who then disappeared.

He later discovered diesel had been mixed into stale bitumen to make it spread further.

Almost a year later, the thin layer of bitumen has never hardened.

Mr Mammone and fellow Wood Wood growers Sam and Marianne De Maio, whose car park was sealed by the same people, reported the incident to police and Consumer Affairs Victoria.

Crime Stoppers Victoria chief executive officer Peter Sprott said the dodgy asphalters were known to have targeted other towns.

A joint campaign by Crimestoppers and Consumer Affairs Victoria will be launched at Bendigo next week to make people aware of the risk of engaging bogus tradesmen.