KUALA LUMPUR, Nov 12 — Datuk Lee Chong Wei’s lawyers have told former national shuttler Razif Sidek to retract defamatory allegations that the badminton world number one was a long-time user of a banned substance, Khairy Jamaluddin said today.

Youth and Sports Minister Khairy said Razif’s claim that Lee was involved in “systematic doping” was unfounded and irresponsible.

“If you want to make a serious allegation like that, you have to show evidence,” Khairy told a press conference after the Retirement Fund Incorporated’s (KWAP) leadership series event here today.

In August, Lee tested positive for anti-inflammatory agent dexamethasone after giving urine samples at the BWF World Championships in August in Copenhagen, where he lost to China’s Chen Long in the final.

Dexamethasone is not a performance-enhancing substance but its use is banned in active competition.

Today, the minister stressed that it was a clinic that had administered dexamethasone to Lee for his rehabilitation from an injury.

Razif, formerly a national badminton doubles player, had made his allegations to news portal The Rakyat Post that were published yesterday.

News agency Reuters reported the Badminton World Federation as saying yesterday that Lee, 32, has been provisionally suspended for an “apparent” anti-doping violation; he now faces a possible ban of up to two years.

On his Facebook account, Lee has denied using drugs to help him gain an advantage.