PARIS - World cycling chiefs have vehemently denied covering up a positive drugs test by retired cycling champion Lance Armstrong, following claims by disgraced former cyclist Tyler Hamilton.

Seven-time Tour de France champion Armstrong is currently weathering the storm of a US federal investigation into claims his former team US Postal used public money to fund a comprehensive doping program.

Federal investigators have traveled to Europe and beyond in a bid to gather evidence for their investigation, calling on a number of former teammates and employees of Armstrong's squad to give testimony.