China's attempts to begin a limited legal trade in elephant ivory should be stopped because it has consistently failed to enforce an existing ban over the past 17 years, an investigation has concluded.

The Chinese government will begin lobbying delegates to the Convention on International Trade in Endangered Species (Cites) this weekend to gain the coveted status of being allowed to import elephant tusks legally from Africa.

But environmentalists are worried that the booming Chinese economy has already created a thriving illegal trade in ivory that the Beijing government has done little to prevent - and may even have encouraged.

Although the African elephant population has recovered since the ivory trade was banned in 1989, in recent years conservationists have reported dramatic declines in numbers in many countries, especially in central Africa, largely due to poaching for tusks.

More than half of the ivory was destined for China, where a thriving industry turns it into tourist trinkets for export to Japan, the Middle East, Europe and the United States.

Environmentalists fear that a limited legal market in ivory will be used as cover for a much bigger and more destructive criminal trade which they believe is already building up in time for the Beijing Olympics next year.

A study by the Environmental Investigation Agency (EIA), a pressure group based in London, has amassed convincing evidence that the Chinese trade has exploded in recent years, even though the importation of ivory has supposedly been strictly prohibited since 1989.

"Ivory traders are now thought to be stockpiling elephant tusks and ivory products for lucrative sales to the hundreds of thousands of foreigners expected to attend the Beijing Olympics in the summer of 2008.

"China has the largest illegal ivory trade of any nation in the world. It is the most significant global destination for illegal ivory," said Allan Thornton, the head of the EIA. "China's long failure to crack down on its massive illegal ivory trade makes a mockery of its claims to be hosting a 'green Olympics'."

Elephants were placed on the list of animals covered by the Cites ban in October 1989, and China formally accepted this in January 1991. In theory only ivory that the Chinese held prior to 1989 could be legally traded. However, the EIA said it has evidence that large amounts of ivory have continued to be imported and exported throughout the 1990s.

Julian Newman, who has met Chinese ivory traders as part of the EIA's investigation, said a global network has been established to smuggle illegal ivory from Africa to China. "The big problem is that the Chinese domestic market is unregulated and provides the perfect cover for the illegal trade," he said.

China introduced a national ivory registration scheme in 2004, which is supposed to ensure that all ivory sold on the open market comes from a registered government stockpile. Since the scheme came into effect the number of ivory-processing operations rose from nine to 17 and the number of registered retailers and ivory wholesalers increased from 31 to 87.

During his visits to China, Mr Newman interviewed several registered ivory traders who admitted that their ivory does not come from old stockpiles.

The EIA claims that official stockpiles of ivory in China are not adequately monitored and that there is increasingly strong evidence that they have been used to supply carving factories in the economic growth zones of southern China. It also claims ivory seized by the government has made its way into official stockpiles.

Mr Thornton said Chinese nationals and companies, some government-owned, are implicated in the illicit export of raw ivory from Africa, and the consequent growth in poaching.

"China's massive illegal ivory trade is not an accident. Failure by the government of China to ensure meaningful enforcement of Cites regulations that prohibit the import and export of ivory resulted in illegal ivory flooding on to the domestic market in the 1990s," Mr Thornton said. "China's demand for ivory is directly responsible for the renewed poaching crisis facing many African elephant populations," he said."

How a giant was brought to its knees

* The African elephant is the largest living land animal and can reach 13 feet in height and weigh up to 16,000 pounds - more than 7 tons.

During the 1970s and 1980s, the species suffered a dramatic decline, largely because of the explosive growth in poaching for the animal's valuable ivory tusks using automatic weapons which became widely available at this time.

No one can be sure just how many elephants lived in Africa before mass poaching, but the population is estimated to have been around 1.2 million. Today, there are probably fewer than 500,000, which is nonetheless higher than it was 20 years ago. the height of the ivory trade, during the 1980s, some 670 tons of ivory per year were exported from Africa - equivalent to the poaching of about 75,000 elephants annually.

Since 1990, when the African elephant was added to appendix 1 of the Convention on International Trade in Endangered Species (Cites), the populations in some African nations have recovered, and the subsequent boom in numbers has led some southern African countries to propose a return to a limited trade in elephant ivory.

As a result, in 1999, Zimbabwe, Botswana and Namibia were allowed to sell a one-off shipment of stockpiled ivory to Japan. Zimbabwe also has dispensation to export locally manufactured ivory carvings for non-commercial purposes.

Now there are moves to allow further shipments of ivory stockpiles, and Japan and China want Cites to give them the status of approved trading partners, which would allow them to import raw ivory legally from Africa. However, conservationists claim that if China is allowed to resume the import of ivory, it will fuel an even bigger illegal trade in poached tusks that could spell a 21st-century disaster for the African elephant.