Searches were also made at two other nearby beaches, but no medical supplies were found.

A department spokesman urged anyone finding syringes to alert them immediately.

''People can make such reports by calling our hotline, informing lifeguards on duty at various beaches or by contacting any of the district hygiene offices,'' he said.

The search was launched after the South China Morning Post reported that 50 used syringes, some still with needles attached, were found by Friends of the Earth volunteers on Sunday.

Friends of the Earth gave the syringes to the Post and they will be sent to an independent laboratory for examination today.

The new find initially prompted suggestions that Rocky Bay beach, declared unsuitable for swimming in 1988 because of pollution, was being used by drug addicts.

But Chris Simpson of KELY drug support group and one Shek O resident said they were not aware that anyone was using the beach.

''As far as European drug users are concerned, I would have thought it was too far out of the way to be used for taking drugs. I think it more likely these are being washed up,'' Mr Simpson said.

This was backed up by the fact that medical supplies and a seaman's survival container were also discovered at Rocky Bay, prompting concern among conservation groups that medical waste is not being properly disposed of and is causing a health hazard.

Medical equipment, including syringes, was washed up on the main beach at Stanley last month, but that consisted mainly of unused items still in their cellophane wrappers.

United Democrats legislator Reverend Fung Chi-wood has urged the Government to take action as the syringes could endanger anyone walking on the beaches, especially if they were contaminated.