Over 1,000 tigers have been killed over the last decade for illegal trade in their skin and bones, a study by wildlife protection groups said.
However, Traffic International, which carried out the study with help from the Worldwide Fund for Nature (WWF), said the official figure was likely to be only a small fraction of the true numbers.
India saw by far the most seizures of tiger parts, followed by China, Nepal, and Indonesia, the British-based group said.
"With parts of potentially more than 100 wild tigers actually seized each year, one can only speculate what the true numbers of animals are being plundered," said Pauline Verheij, joint Traffic and WWF Tiger Trade Programme Manager and an author of a report on the study.
A study issued in September by the US-based Wildlife Conservation Society said Asia's tiger population could be near extinction, with fewer than 3,500 remaining in the wild.
Tiger parts reported in trade ranged from complete skins, skeletons, and even whole animals - alive and dead - through to bones, meat, claws, teeth, skulls, penises and other body parts, the report said.
A total of 481 parts seizures were analysed, suggesting at least 1,069 tigers killed and a maxiumum of 1,220, between January 2000 to April 2010.
That works out to an annual average ranging from 104 to 119 tigers.
Though India remains a major player in the supply of tiger parts, the roles of Indonesia, Nepal, Thailand and Vietnam as suppliers are growing as demand remains for tiger products.
"The data show that illegal tiger trade continues unabated despite considerable and repeated efforts to curtail it on the part of tiger range and consumer countries, inter-governmental organizations, and NGOs," the report says.
Tiger parts are used in many cultures as good luck charms, decoration or in traditional medicines, with the animals symbolising strength, courage and luck.