Singapore's retail sales increased by 6.9 percent in June on a year-on-year basis, mainly due to a spike in sales of motor vehicles, said the Department of Statistics Singapore (SingStat) on Friday.

On a month-on-month basis, retail sales rose by 0.6 percent in June. Excluding motor vehicles, retail sales decreased 3 percent.

The total retail sales value in June was estimated at 3.5 billion Singapore dollars, higher than 3.3 billion Singapore dollars in June in 2014.

Sales of motor vehicles registered a record surge of 85.2 percent in June on year, while retail sales of department stores and supermarkets also rose by 1.9 percent and 2.7 percent year-on- year, respectively.

On the other hand, sales of petrol service stations declined by 16.7 percent, respectively, while sales of food and beverage services also saw a decrease of 5.1 percent.

The total sales value of food and beverage services in June 2015 was estimated at 613 million Singapore dollars, lower than the 646 million Singapore dollars in the same period of 2014.

The Retail Sales Index and the Food and Beverage Services Index measure the short-term performance of retail and Food and Beverage service industries based on their sales records. The sales figures exclude taxes.