Paris - The Court of Arbitration for Sport (CAS) may not be able to rule on the Alberto Contador doping case before the start of the Tour de France because a lengthy procedure lies ahead, CAS's general secretary said on Thursday.

The International Cycling Union (UCI) is appealing against the Spanish federation's decision to clear the triple Tour champion, who tested positive for the banned anabolic agent, clenbuterol during last year's race.

"I am puzzled that the UCI have waited until the very last moment to appeal," Matthieu Reeb told Reuters.

"We lost a few precious weeks because of that."

He added that CAS had yet to be formally notified of the appeal: "I imagine it will be sent by mail tonight so we should have it tomorrow."

The World Anti-Doping Agency (WADA) has yet to announce its plans but can still join the appeal within 21 days.

If the parties really want a quick decision, "we can arrange that", Reeb added.

"But from what I heard from one of his lawyers, we are heading for a fierce defence. I am pessimistic we can make a ruling before the end of June."

The Tour de France starts on July 2 and as long as CAS has not issued a ruling against him, Contador, 28, will be able to compete.

"There could be problems that slow down the process, such as the choice of experts on the panel, the choice of the language," Reeb said.

Contador, who has denied any wrongdoing and said clenbuterol was found in his system after he ate contaminated meat, is currently riding the Tour of Catalunya where he is the overall leader.