Santiago Perez was second in the Tour of Spain

Phonak team-mate and Olympic time trial champion Tyler Hamilton tested positive for blood transfusions at both the Tour of Spain and the Athens Olympics.

"I'm really shocked by the news and by the behaviour of the International Cycling Union," Perez told cycling website todociclismo.com.

"All I can say is I have not undergone any type of blood transfusion."

Perez, who finished second in this year's Tour of Spain, cast doubts on the reliability of the testing procedure employed to detect blood doping.

"I received a very confusing and contradictory communication telling me of the results of the analysis.

"I am sure that the truth will come out very soon and it will show that none of what they are accusing me of is true."

The 24-year-old said the test had been analysed in Lausanne earlier this month and the B sample was checked this week.

Hamilton was cleared to keep his Olympic gold after the International Olympic Committee decided his B test was "non-conclusive" because the sample had been destroyed as a result of being deep-frozen.

However, the American has been suspended by the Phonak team pending investigations into the case.

Another Phonak rider, Switzerland's Oscar Camenzind, was banned for two years after testing positive for EPO shortly before the Athens Games.