The Office of Fair Trading is warning Redland residents not to buy cheap entertainment systems being offered for sale in the Cleveland area.
A spokeswoman said the department had received reports from consumers of people selling home entertainment systems from the back of a white van.
“Goods sold out of the back of a vehicle are usually overpriced, damaged or do not live up to what's promised,” she said.
“Buyers have no way to get a refund or exchange if the item is faulty as car boot traders usually vanish after the sale.”
The department wants people to contact it on 13 74 68 if they are contacted by these people so their movements can be tracked and other consumers warned.
Last year and in 2016 so-called bitumen bandits hit the Redlands, offering cheap driveway paving.
They knocked on doors, saying they had done a job nearby and had bitumen left over which would enable them to do a cheap job.
The department warned residents should be wary if approached by traders offering bitumen laying or other home maintenance in return for cash.
It was illegal for door-to-door traders to take upfront payments or deposits for services valued at more than $100.