WASHINGTON: If reports are to be believed, illegal "tiger bone wine" is still being made and sold by some animal parks in China.

Evidence emerged when researchers from a UK based agency, namely the Environmental Investigation Agency (EIA), who were investigating into the matter, said that they were offered drinks made from tiger carcasses soaked in rice wine.

According to the NGO, its investigators found that the wine, deemed to be a health tonic to treat conditions such as arthritis and rheumatism, was being openly advertised at the parks.

The park's staff said that the wine was made from tigers that had died after fighting with other big cats at the venues.

One park produced what they said was a government permit that allowed the sale of the tiger-derived wine on the premises, but the EIA researchers said it was not possible to verify whether the permit was genuine.

The EIA said that a senior worker, when questioned by its researchers, said that she was aware that the tigers were a protected species and trading of any part of the animals "in the open market" was prohibited.

But, the agency said that she went on to explain that the permit allowed "closed market" sales of the wine; in other words, it could be sold from the park's premises.

Since the 1980s, a number of "tiger farms" have been set up in China. These establishments are believed to house about 5,000 captive tigers, possibly more than remain in the wild.

Debbie Banks, head of the EIA's tiger campaign, called on the Chinese authorities to close down the illegal trade.

"We want other parks with similar tiger attractions to be investigated to see how widespread this tiger-bone wine-making practice is," she said.

"We also want the authorities to give a clear message to the business community that this illegal trade will not be tolerated," she added.

There are estimated to be 3,500-7,500 tigers left in the wild, compared with roughly 100,000 at the start of the 20th Century.