Software developed by a company in New Zealand (where winding back odometers of used cars imported from Japan has been rife) finds accurate figures elsewhere in a car's computer system.

The Sydney Morning Herald motoring website, drive.com.au, said most modern vehicles use several computers to keep them running and, while some crooked dealers can successfully rewind the distance in the instrument cluster, the true readings are hidden in several other parts of the car not seen by the driver or the crook.

Auckland-based Optimech has developed software to "read" information from the computer systems of the latest BMW, Mercedes-Benz, Audi and Volvo models as well as a wide range of Japanese vehicles, the report said.

"The distance information is stored in four separate places in some instances, and on some vehicles it is contained in the chip in the ignition key; in that case, we can read the distance a car has travelled by 'interrogating' the key," proprietor Steve Ward told the website.

Engineer Ward reportedly moved into detecting illegal odometer tampering after falling victim to it. Previously involved in importing cars to NZ - where there are no import restrictions on second-hand vehicles - he saw an opportunity to provide a detection service.

"Clocking" remains a problem. "We checked 12 cars which had been imported recently from Singapore," he told drive.com.au, "and 10 of them had odometers which had been altered."

The report said Ward was in Australia explaining the technology to automotive clubs including the NRMA, in the hope they will pick it up and add the checks to inspection services.

He reportedly suggested that, while Australia may not import anywhere near as many second-hand vehicles as New Zealand, the "grey import" business, bringing in small numbers of specialised vehicles, is one area where buyers need protection as such vehicles lack the mileage history that is recorded when cars change hands.

Drive.com.au said Optimech does an inspection for prospective buyers in New Zealand, giving "clean" cars with no signs of tampering a certificate of validation. It currently checks about 2,000 vehicles a month in NZ and Japan, where it has a permanent staff of four people, and also provides expert evidence in fraud prosecutions.