An Afghan boxer has been provisionally suspended for failing a doping test at the Asian Games, the International Testing Agency said, the first reported drugs case at the event.

The 37-year-old Mohammad Khaibar Nooristani, who was defeated on Monday in the preliminary rounds of the 71kg weight class in Hangzhou, tested positive for two banned substances, the ITA said.

Both were anabolic steroids.

The boxer was tested four days before his bout but it takes time for positive results to come through.

"The sample was collected by the ITA at the Asian Games Hangzhou during an out-of-competition anti-doping control performed on September 21, 2023," the body said Thursday.

"The athlete has been informed of the case and has been provisionally suspended with immediate effect. He has the right to request the analysis of the B-sample."

Speaking earlier this week, Mani Jegathesan, an adviser to the Olympic Council of Asia's anti-doping committee, warned that drug cheats at the Games would be rooted out.

"Every athlete participating in these Games must understand that they could be picked at any time," Jegathesan warned.

"That is the best step to ensuring we have a clean event."

There are about 12,000 athletes at the 19th Asian Games, more competitors than at the Olympics, and Jegathesan admitted it would be impossible to test them all.

Instead, they will prioritize, including picking out those who break world or Asian records.

They will also home in on athletes if they receive "intelligence".