HONG KONG (AFP) - Chinese women's hammer thrower Zhang Wenxiu had her 2014 Asian Games gold medal reinstated on Wednesday after overturning a positive drugs test, the Olympic Council of Asia (OCA) announced.

China's track and field team at the Incheon Games were rocked by news of the test five days after she threw 77.33 metres to claim gold on Sept 28.

A sample provided by Zhang before the competition had shown the presence of zeranol, a banned substance. She was disqualified and stripped of her gold medal.

She appealed and the OCA said on Wednesday that further independent testing last month had shown that "the presence of zeranol was, as Zhang asserted in her appeal, caused by eating contaminated food".

Zeranol is found naturally in a fungus associated with cereal crops and can even permeate into the body through contact with the skin.

"Ms Zhang did not ingest the Prohibited Substance detected in her sample," the statement continued.

"Based on this new information and supported by Wada (the World Anti-Doping Authority), the Olympic Council of Asia recognises that Ms Zhang did not return an Adverse Analytical Finding for the presence of zeranol, nor therefore commit an Anti-Doping Rule Violation during the 2014 Asian Games."