HONG KONG (AFP) - Hong Kong's government said on Friday it would stop serving shark fin at official functions as "a good example", following years of lobbying by conservation groups.

The southern Chinese city is one of the world's biggest markets for shark fin, which is viewed by many Asians as a delicacy and is often served as a soup at expensive Chinese banquets.

Along with sharks' fin, bluefin tuna will also fall under the ban, which was prompted by what the authorities called "conservation concerns".

"The exclusion of these... items from official menus is a start and also serves as an example of raising public education and awareness on sustainability," a government spokesman said in a press release.

"The government is determined to take the lead and set a good example on this front," he said.

Trade in shark fin is not regulated in Hong Kong except for that involving three species - basking shark, great white shark and whale shark - where the trade is restricted under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Cities), to which Hong Kong is a signatory.

Non-profit organisation the Pew Group estimates more than 70 million sharks are killed annually for their fins, leaving up to a third of open-water species on the brink of extinction.