BEIJING - China's political advisors on Thursday called for enhanced supervision over online antique trading, after millions of cultural relics were sent abroad illegally.

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Shan Jixiang, director of the State Administration of Cultural Heritage and member of the National Committee of the Chinese People's Political Consultative Conference (CPPCC), China's top political advisory body, said the Internet was widely used in smuggling cultural relics out of the country.

Statistics from the State Administration of Cultural Heritage show that over one million antiquities, worth a total of more than 1 billion yuan ($152 million), were sold online last year.

China has lost 17 million pieces of cultural relics abroad, according to the government survey. "Nowadays, smugglers are emboldened to sell relics illegally via online trading," Shan said on the sidelines of the ongoing CPPCC National Committee session.

In 2007, customs officials found 47 pieces of cultural relics in 10 packages mailed to a French buyer by a relics dealer surnamed Liao of Wuhan, capital city of central China's Hubei Province.

Liao began selling antiques abroad via e-mail in 2005.

In 2009, another dealer surnamed Ding of Chengdu, the capital of southwest China's Sichuan province, was caught selling ancient coins to foreign buyers through his shop on eBay.com, a well-known e-commerce website.

Ding sent 66 precious coins abroad by registered mail, including two under State protection.

An eBay seller, speaking under condition of anonymity, who uses the site to deal relics internationally, said that many foreign buyers are interested in Chinese antiques and cultural relics.

"Cultural relics forbidden to leave the country bring more profits," he said.

Chinese law forbids the free trade of relics except through certified stores and auctions.

The law also prohibits cultural relics dated before 1911 from leaving the country.

There are no specific regulations on internet-based relics trading.

Shan said the cultural relics department is prepared to examine the operating qualifications and to regulate the transactions of over 200 existing websites involving the dealing of cultural relics and antiques.

Yu Hui, another member of the CPPCC National Committee and researcher of the Palace Museum, said customs and cultural relics authorities should work together to effectively identify true relics and antiques from imitations.

Customs authorities in 16 provinces and cities have set up special mechanisms for border exit inspections of cultural relics, while other provinces and regions are still lax in checking outgoing relics, including courier services, which leaves many loopholes for smugglers.

"Joint efforts should be made to prevent China's cultural relics being taken aborad illegally," Yu said.