Dane Rasmussen is a Monaco resident and has had cycling a licence from the principality since January 1, 2007. The Rabobank rider was a Mexico resident the two previous years.

"It is questionable from a legal point of view from ADD to be authorised to do tests with Michael outside Denmark because Michael has a licence from another federation," Rabobank's lawyer Harro Knijff told a news conference.

"Until January 1, he had a licence from the Mexican federation and as of January 1, he has a licence from the federation of Monaco.

"It is highly questionable from a legal point of view that ADD have the competence to do tests outside Denmark," he added.

Asked if he had ever been tested by Mexico or Monaco's authorities, Rasmussen said: "No, I have never been tested by the Monaco authorities or by the Mexican authorities."

Rasmussen often trains in Mexico, the home country of his wife.

The 33-year-old, who has led the Tour since the eighth stage of the race, has been at the centre of a controversy since the Danish Cycling Union (DCU) announced last Thursday he had been dropped from the national team for the world championships.

The DCU has since gone on to query Rasmussen's eligibility to compete saying the rider has received four warnings for failing to provide information of his whereabouts during training.

Under International Cycling Union (UCI) rules, a rider must inform the sport's governing body of his personal schedule so random tests can be conducted.

If the cyclist fails to do so, he receives a warning. Three such warnings over a rolling 18-month period is considered the equivalent of a positive test and results in a two-year suspension.

The UCI said Rasmussen had received two warnings from them.