Retail sales dropped by 11.5 percent in May compared with the same month last year, extending a losing streak to three months.

Data released by the Census and Statistics Department on Tuesday showed that sales slid to HK$30.5 billion.

The drop came after a 14.7 percent fall in April and a 7 percent decrease in March.

In a statement, the government blamed the latest slump on changes in spending patterns of visitors and residents, as well as the strength of the Hong Kong dollar.

The government said a recent increase in duty-free allowances for mainland visitors should help local retailers.

"The retail sector may still face some challenges in the near term. However, the Central Government's recently announced measures benefitting Hong Kong, including the further enhanced Individual Visit Scheme and the increase of duty-free allowance for luggage articles for mainland resident visitors, should help stimulate retail businesses," a government spokesperson said.

The spokesperson added that the authorities will continue to stimulate the local economy and market sentiment by hosting mega events.

Speaking in an online press call, the executive director of the Retail Management Association, Bond Law, said retails sales are expected to continue falling in July and August.

"We believe that the market will remain sluggish for the second half of this year, considering the speedy business downturn, together with high rent and manpower costs," he explained.

"Other economic factors, such as the strong Hong Kong dollar, also pose challenges to the retail industry. The difficult situation is expected to continue for some time."