Revenue Commissioners, Customs and Excise and Gardai have been investigating the practice after reports of significant fuel contamination in the west border regions and midlands.
Petrol stretching involves adding up to 10 percent of kerosene to petrol before selling it to unwitting drivers.
Kerosene, which is used as a fuel for heating, is widely available for just 80c per litre, as opposed to petrol which is close to double that at €1.55.
It's estimated that over 100 petrol cars have already had their engines badly damaged by petrol stretching, including some rented 142-registration cars.
Kerosene will damage an engine even more quickly than most laundered diesel and vehicles with smaller petrol engines are most at risk. Motorists should watch out for a lack of power and misfiring of the engine. They may also experience a knocking noise. Report any incidents to An Garda.
