A urine sample taken from the Hong Kong player in late June tested positive for the drug, the world governing body have announced.

The 31-year-old, who won the bronze medal at the 2004 Olympics in Athens, claimed she took drug - used by asthma sufferers or as a weight-loss aid - unknowingly, as it was contained in a Chinese medicine to treat a fever.

BWF chief operating officer Thomas Lund said in a statement it was the body's first drug ban in recent years.

"The case sends a strong message to elite athletes in the sport, who need to be aware of prohibited substances and the consequences of taking these - either deliberately or inadvertently," he said.

Zhou, the 2002 Asian Games gold medallist, denied she had deliberately taken banned performance-enhancing drugs and said that she plnanned to appeal.

Zhou was born in Nanning, China, but retired after Athens following her controversial defeat in the semi-final to teammate Zhang Ning, where it was claimed she deliberately lost the second set on the orders of the team coach to ensure she ensured her colleague remained fresh for the final.

She resumed her international career in 2007 after switching allegiance to Hong Kong.