The beach was closed and will reopen at 9am today, the Leisure and Cultural Services Department said last night.

The Marine Police and Government Flying Service completed checks in nearby waters and confirmed no further shark sightings, it said.

The Agriculture, Fisheries and Conservation Department is studying the carcass to determine the type of shark and its age.

The three juvenile sharks spotted yesterday - about 60cm to a metre long - were seen near the Hoi Ha Wan Marine Life Centre, the location of five out of 10 recent sightings.

Swimmers at Stanley Main Beach seemed unconcerned by the news, with many staying in the water despite loudspeaker warnings and signs.

'Only a shark's body was found. I think the chance of encountering a shark is low,' said Kwong Chi-hang, 18. He said he had as much chance of encountering a shark as winning the Mark Six.

Kwong Dai-che, 58, had been swimming with his family for more than two hours. 'If sharks attack, those people, not us, will die first,' he said pointing towards people in boats outside the shark net.

A leisure department spokesman warned swimmers to stay out of the water in areas not protected by shark nets. 'Swimmers should stay in the shark-netted areas and avoid swimming at dawn, night or dusk,' he said.

Shark nets have been installed at 32 out of 41 gazetted beaches and the department has no plan to place more. All six gazetted beaches in Sai Kung have shark nets.

A spokesman assured the public that all the shark nets it managed were in good condition. 'We hope people can understand that it is impossible to install shark prevention nets at each and every beach in Hong Kong,' he said.

Shark expert Andy Cornish said it was unfortunate that nets sometimes killed these fish and other marine creatures. '[Killing sharks] is not the intention of the shark net,' said Mr Cornish, conservation director of WWF Hong Kong. He said the size of the mesh was the problem. 'No matter what size the holes are, there may be some animals that get caught.'

As shark sightings rose, the fisheries department yesterday warned against trips to watch or hunt them in marine parks.

'As far as the marine parks are concerned, unauthorised fishing activities or hunting of animals is strictly prohibited,' a spokesman said. 'For their own safety, visitors should avoid any close encounter with sharks ... even watching them from a boat.'

Several shark attacks have occurred in Hong Kong waters since the 1990s. Three people were killed by sharks within a fortnight in the waters off Sai Kung in 1995. A former Hong Kong swimmer in the Asian Games died in 1995 after his right leg was bitten off by a shark.

Where they were seen

June 15 A diver reported sighting four sharks at Port Shelter, Sai Kung

June 18 A swimmer reported sighting a shark at Repulse Bay

July 2 Three small sharks were sighted near the Hoi Ha Wan Marine Life Centre, Sai Kung

July 3 A small shark was sighted near the Hoi Ha Wan Marine Life Centre

July 11 A small shark's carcass was found at Stanley Main Beach; Three juvenile sharks were sighted near the Hoi Ha Wan Marine Life Centre