Asian Games organisers on Tuesday expelled Malaysia's wushu gold medal winner Tai Cheau Xuen after she failed a drug test, officials said.

Tai was found to have taken the stimulant sibutramine, the Olympic Council of Asia said in a statement.

Tai is the third positive drug test at the Games after a Tajik footballer and Cambodian soft tennis player. The Asian Games involves 9,500 athletes from across the region.

"The competitor has been disqualified from the competition as well as these Games, and as such her accreditation cancelled and her medal withdrawn," said the statement.

The official announcement of the failed test was delayed because Tai and the Malaysian Olympic Committee had asked for the B-sample to be examined, officials said.

A Tajik footballer, Khurshed Beknazarov, and a Cambodian soft tennis player have already been expelled for failing tests.

Nineteen-year-old Cambodia Yi Sophany was also found to have taken sibutramine, which is widely used as a dietary supplement to control weight.

About 1,900 doping tests will be carried out on the Asian Games athletes, according to the OCA medical committee chairman M. Jegathesan.

According to Jegathesan, there are three kinds of doping failures.

There are the "hard-core" cheats who deliberately take the "magic pill" because they think it will help them to win. There are competitors who are pushed into doping by their coaches.

And there are athletes who get caught through "ignorance" just by taking medicines and diet treatments.

The Cambodian athlete told the OCA that she had taken sibutramine as part of a beauty treatment, officials said.

And they acknowledged that it probably would not have helped her performance.

But the OCA is obliged to follow the World Anti-Doping Agency rules and list of banned stimulants.

Jegathesan said that neither of the first two cases reported were probably intentional. "I don't think there was ever any intention to use these to cheat," he said.

"But we cannot make an exception to the rule simply because we are sympathetic. We have a job to do, to protect the clean athlete," he added.

On winning, Tai had dedicated her victory to all Malaysians for their solid backing for the national contingent in Incheon.

"I also want to thank the National Sports Council and Olympic Council of Malaysia for the support they have given me," she said.