Hong Kong authorities issued 300 verbal warnings to people visiting Sharp Island on the first day of mainland China’s Labour Day “golden week” holiday, when thousands flocked to see attractions in the city’s Unesco Global Geopark.

The Agriculture, Fisheries and Conservation Department said on Saturday that the number of visitors to Sharp Island a day earlier had “exceeded expectations”, with about 3,000 visitors making the trip, prompting additional frontline staff to be deployed.

Hong Kong’s Sai Kung district has become a popular tourist destination owing to its natural scenery and well-established hiking trails, with many of the around 250,000 mainland arrivals on the first day of the five-day holiday headed there.

But the area’s growing popularity, which is partly due to its heavy promotion on mainland social media, has triggered concerns about the potential ecological damage arising from overtourism.

The department also said that about 5,700 people had visited the High Island Reservoir East Dam on Friday, resulting in what it described as “extremely busy crowds.”

“Staff maintained order and managed the flow of people at the trail entrances and the viewing platform,” it said. “Visitors cooperated with the instructions of on-site staff and waited patiently; overall, the situation was orderly.”