According to the Land Transport Authority, parallel-imported car sales between January and September this year have fallen by 13.8 percent.
Civil servant Mr. Mohamed Anwardeen is taking parallel importer SG Vehicles Global to court over an undelivered car, which he ordered over a year ago.
Royal Automotive made headlines last November when its former sales representative Chua Peng Jun was charged in court for misappropriating $414,564.
Another car parallel importer has failed to deliver vehicles on which deposits have been paid - the second such case in less than a month.
Non-authorised agents hold a 22 percent share of the market in the first quarter, with Honda, Toyota, Mercedes-Benz being hot sellers.
The owner of a car parallel importer who allegedly took deposits from customers but never produced their vehicles has left the country.
Parallel importers in Singapore are resorting to a ploy to trade their new cars as used cars, in a bid to avoid hefty taxes.
LTA has taken parallel importer I-Auto to court over false manufacture dates for a Rolls-Royce Phantom imported for an Indonesian businessman.