Total retail sales fell 8.4 percent from a year earlier in January, after rising a revised 6.3 percent in the previous month, according to data from the Singapore Department of Statistics.
Sales of motor vehicles fell 9.8 percent from the year before and fell 20.9 percent from December.
Singapore, one of the world's most expensive places to own a vehicle, announced in October last year that it would not allow any growth in its car population from February, citing the city-state's land scarcity and billions of dollars in planned public transport investments.
The on-year fall was also attributed to the Lunar New Year holidays, which fell in January last year but was celebrated February this year, Singapore Department of Statistics said in a press release.
On a month-on-month and seasonally adjusted basis, total retail sales fell 5.4 percent in January after rising a revised 0.6 percent in the December.