Hong Kong saw more than 4 million visitor arrivals in May, fuelled by the mainland's Labour Day Golden Week holiday and citywide events, the Tourism Board said on Monday.

In a statement, the board said last month's arrivals totalled 4.08 million, representing a 20 percent year-on-year increase.

This surge contributed to a strong first five months of the year, with total tourist arrivals topping 20 million, a 12 percent rise from the same period last year.

About 15.2 million arrivals between January and May were from the mainland, marking a 10 percent rise from the previous year, whereas non-mainland visitors totalled about 5 million, an 18 percent increase, with significant growth from Taiwan, Japan, South Korea, Indonesia and the Philippines.

Meanwhile, the Airport Authority said it handled 4.86 million passengers in May, an increase of almost 20 percent compared with a year ago.

The authority attributed the growth to more transfer and transit passengers, particularly to and from the mainland and Southeast Asia.

It added that cargo volume recorded a 1.4 percent year-on-year increase last month to 422,000 tonnes, supported by a 12.7 percent rise in transshipments, with Europe and the Middle East being key contributors.