A 50-metre mainland cargo vessel ran aground at Butterfly Beach in Tuen Mun yesterday after it suffered engine problems and drifted into shore, damaging the shark net.
The vessel is the the second container ship to run aground in Hong Kong's busy shipping lanes this month and the fourth this year.
All seven mainland crew members on the Sui Hai Yun 382 were uninjured in the incident, which happened at about 1pm as the vessel was heading to a Tuen Mun pier to unload goods.
Marine police launches were sent to the scene after a report was received that the 760-tonne vessel had run aground at the beach off Lung Mun Road, where families had been enjoying a day at the seaside.
"An initial investigation indicated that the vessel broke down because of an engine problem," a police spokesman said.
"Due to strong winds, the vessel was suspected to have been blown into the shore."
Although some families remained at the beach, the Leisure and Cultural Services Department said the area around the ship had been closed off.
"Red warning flags have been hoisted at the beach and swimmers are asked to stay out of the water," a spokesman said.
By midnight last night, the ship's operators had removed the vessel.
The department said tests would have to be carried out to determine the extent of damage to the shark net.
The Marine Department said there had been no damage to the vessel and there was no report of any oil leakage.
"We are still checking what damage has been caused by the vessel and investigating the cause of the incident," a spokeswoman said.
It was the second mainland cargo vessel to run aground in the city this month and the fourth this year.
On February 21, a 2,500-tonne Vietnamese vessel carrying 2,800 tonnes of cement from Nansha port in Guangdong province to Indonesia listed before hitting the rocky beach at Tung Wan Tsai on Cheung Chau after it had refuelled in Hong Kong.
On April 6, the 193-metre German-registered Hansa Constitution ran aground at Pok Fu Lam, just feet from the sea wall and a path popular with joggers.
Fire chiefs said it had suffered a mechanical malfunction while on its way to Shenzhen.
Watch: Container ship runs aground off Pok Fu Lam
On June 2, a 63-metre mainland-registered cargo vessel carrying construction waste ran aground off northern Cheung Chau. According to the Marine Department, the vessel still remains grounded and a salvage plan is being arranged.
In Hong Kong, 38 beaches are protected by shark prevention nets. Two people were killed by sharks within days in the waters off Sai Kung in 1995.
Tso Kam-sun, 44, a former Hong Kong swimmer in the Asian Games, was found dead on June 1, 1995, after his right leg was bitten off by a shark.
A day later, hairdresser Herman Lo Cheuk-Yuet, 29, was mutilated in a second fatal attack at Sheung Sz Wan beach.