In June alone, the city state welcomed 1.18 million international visitors, down 4.9% from a year earlier and marking its weakest monthly tourism performance in the first half of the year, according to data from the Singapore Tourism Board (STB).

Overnight arrivals declined more sharply, falling 8% year on year to 850,380, while the average length of stay slipped 3.0% to 3.59 days, indicating softer visitor demand.

Tourists take photos at the Merlion Park in Singapore, Jan. 11, 2017. Photo by Reuters

China remained Singapore's largest source market in the first half of the year, contributing 1.53 million visitors, up 3.7% from a year earlier.

However, declines in visitors from Indonesia and India weighed on overall tourism growth.