Merckx called to testify

Merckx's son Axel is a former team mate of Landis, who is battling to keep his 2006 Tour de France title after testing positive for elevated testosterone to epitestosterone levels.

Landis has denied taking performance enhancing drugs and is currently appearing before a U.S. arbitration hearing into the case taken by the U.S. Anti-Doping Agency's.

Merckx, 61, winner of more Tour de France stages than any other cyclist, told Belgian TV: "I do not want to be mixed up in this, not from close by nor from afar. I have nothing to say and therefore will not testify.

"I know nothing about this business and I therefore don't see in what way I can help clarify things. I've asked myself why I have been invited to testify."

At the hearing in Malibu, Landis's spokesman Michael Henson told Reuters: "He's a standby witness. We may not use him if we don't discuss tactics. Right now, the focus is on science."

Last year, Merckx was an adviser to Landis' Phonak Team, of which his son Axel was also a member.