Their bans were set to end in December, but both appealed.

The CAS today ruled Powell and Simpson are eligible to compete immediately but may have to serve the remainder of their initial suspension later, if their appeals are not accepted.

A hearing is scheduled for July 7 and 8.

American sprinter Tyson Gay, who failed drug tests under different circumstances last year, had his ban reduced to one year for providing assistance to the United States Anti-Doping Agency and will return to competition July 3.

Powell and Simpson, 29, have both blamed their Canadian trainer Christopher Xuereb for providing supplements that contained traces of the substance - a claim he has denied.

"The Court of Arbitration for Sport upheld today the application for a stay of the execution of the suspension currently served by the Jamaican sprinters Asafa Powell and Sherone Simpson pending the resolution of the arbitration conducted before the CAS," the Lausanne-based CAS said in a statement.

"The athletes are free to compete from now on but may have to serve the remaining part of their ban later if the sanction is eventually confirmed by CAS.

"Both athletes filed appeals at CAS against the decisions of the Jamaica Anti-doping Disciplinary Panel Tribunal of 8 and 10 April 2014 to suspend them for a period of 18 months, starting on 21 June 2013.

"The athletes put forward that the offense (sic) committed is minor and request that the suspensions be reduced to 3 months.

"The Jamaica Anti-doping Disciplinary Panel Tribunal sanctioned the athletes following a positive anti-doping test with the banned substance Oxilofrine."

Sherone Simpson (left), celebrating her Olympic 100 metres silver medal at Beijing 2008, has had her drugs ban temporarily lifted by the Court of Arbitration for Sport ©Getty Images

Powell reacted by posting his joy on Twitter.

"God is good! Thank you to CAS for granting me this stay...I look fwd to my day in Court. Until then see u ...," he wrote.

"Both Asafa and Sherone are elated," said Tara Playfair, Powell's publicist, expanding on his reaction.

"They are both back home and at the gym, continuing their preparation for any upcoming meets, and they are looking forward to seeing their fans.

"They are very grateful for the support they have received from their fans over the last 11 months,"

The stay of execution clears the way for the athletes to compete at  the National Championships due to take on June 26 and 29, where Jamaica's team for the Commonwealth Games in Glasgow will be selected. 

It had been reported last week that a deal had been agreed between Powell's representatives, the World Anti-Doping Agency and the International Association of Athletics Federations for him to receive a truncated ban of 11 months. 

But the deal required the blessing of the Jamaica Anti-Doping Commission, which refused to sign it because they claimed it was against their rules. 

Garth Gayle, general secretary of the Jamaica Athletics Administrative Association (JAAA), has confirmed that Powell and Simpson will be allowed to compete at the National Championships and selected for Glasgow 2014 if they meet the qualifying criteria.

Powell, a member of Jamaica's 4x100m relay team that won the Olympic gold medals at Beijing 2008, last competed in the Commonwealth Games at Melbourne 2006, where he won the 100m. 

At the same Games, Simpson won gold medals in the 200m and the 4x100m relay. 

"All parties are bound by the CAS ruling," said Gayle. 

"The JAAA is one of those parties, so we have no recourse but to abide by their ruling."

Contact the writer of this story at [email protected]


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January 2014: Jamaican sprinter Powell claims drugs came from trainer as doping trial gets underway