The number of mainland visitors to Hong Kong during the May 31 to June 2 Dragon Boat Festival fell 2.5 percent compared with the same period last year, the first drop in five years, according to So Kam-leung, the special administrative region's Secretary for Commerce and Economic Development.

He also said retail sales in April this year suffered their biggest decline since February 2009 amid fears that reducing mainland visitors and cancelling the special visa for Shenzhen residents would be a big blow to Hong Kong's economy.

At a media session following a luncheon of the Lions Club of Happy Valley, So took questions on what costs Hong Kong incurred in curbing mainland visitors, and what the city can afford.

He listed the growth rate in mainland tourists in the past four years, saying the decrease for the three-day festival may not represent an accurate change in tourist numbers, as figures in May and the following months will also be taken into account.

So said tourism is one of the four pillar industries of Hong Kong which accounts for 4.7 percent of total local output. The industry has around 250,000 workers and plays an important role in promoting peripheral industries.

So added that he hopes the topic will lead to further discussions and suggestions from all sides.