The head of Spain's cycling federation has warned Alberto Contador that appealing against his ban for failing a dope test could lead to a stiffer penalty than the provisional one-year suspension.

The triple Tour de France champion has 10 days to appeal the federation's preliminary decision to ban him for a year, communicated to the rider on Wednesday, before a final verdict is reached.

He also has the possibility of taking the case to the Court of Arbitration for Sport, but RFEC president Juan Carlos Castano said that might be counterproductive.

"If Contador appeals to CAS I see it as very difficult that the case won't become more complicated, including even making it worse," Castano said in an interview with Spanish television broadcast on Friday.

Contador has been suspended provisionally since August after testing positive for a small amount of the banned anabolic agent clenbuterol during last year's Tour, his third victory.

He has denied deliberate wrongdoing, saying the failed test was due to contaminated meat.

Reuters