Consumer Protection are warning regional businesses about 'Bitumen Bandits with reports they are in the South West area.
A Myalup business paid the six men $15,000 for a new driveway last week and they have yet to return to complete the work.
An Australind business was also targeted with the owner refusing to pay $20,000 for what he considered was unsatisfactory quality of work.
Two of the men who are leading the workers are reported to have English or Scottish accents.
It's feared that they could target home owners, if they haven't already, and move their operations into other regional areas or to the outskirts of the Perth metropolitan area.
'Bitumen Bandits' go door to door and offer to resurface driveways on the spot and engage in high pressure sales tactics.
These terrible tradies also break door to door, or unsolicited, trading laws which give consumers the right to a ten business day cooling off period if they are approached uninvited.Consumer Protection Commissioner Gary Newcombe
The work is usually sub-standard with inferior quality material being used and, in some cases, the driveways are too thin to support the weight of a car.
Consumer Protection Commissioner Gary Newcombe said these travelling conmen should be avoided as they were likely to take your money and run.
"They are not legitimate traders whose aim is to do a good job, they just want to get their hands on your money and then disappear. Their work is usually sub-standard and their prices are hugely inflated," Mr Newcombe said.
"Consumers should resist their high pressure sales tactics and ignore their claims of offering a good deal. Those looking to get bitumen work done should instead get multiple quotes from reputable tradespeople, especially considering it is normally expensive work.
"These terrible tradies also break door to door, or unsolicited, trading laws which give consumers the right to a ten business day cooling off period if they are approached uninvited. It is illegal to take money or carry out any work during this time.
"Once gone, it's almost impossible to track them down after the home owner realises the work does not meet minimum standards. So be on alert and, if approached, send them on their way and contact Consumer Protection to report their whereabouts."
To report travelling conmen, call Consumer Protection on 1300 30 40 54. Information such as descriptions of the offenders, vehicle registration numbers or business names used would be useful.