The Asian Games was hit by its first positive drugs test on Friday, the Xinhua news agency reported and identified the athlete as a Kazakh.
The Olympic Council of Asia has scheduled a news conference at 1730 local time where full details were expected to be revealed.
On the eve of the November 12-27 showpiece, the China Anti-Doping Agency said it planned to test 1,500 urine samples and more than 200 blood samples.
All samples are being tested at the agency's world-class lab in Beijing, which conducted drug screenings for the 2008 Summer Olympics. At the 2006 Asiad in Doha, four weightlifters were kicked out for flouting drugs rules.
Myanmar lifters Kyi Kyi Than and Oo Mya Sanda, a silver medallist in the 75kg division, both returned positive tests.
Uzbekistan's Elmira Ramileva also tested positive for an anabolic steroid and teammate Alexander Urinov was found to have taken cannabis.