Virenque was the most high-profile of a series of riders who were barred from the event earlier this month because of allegations of doping. The Frenchman, who rides for the Italian Polti team, was "not welcome" because "his presence would be incompatible with the image of the Tour, and the one we want to preserve," said Jean-Marie Leblanc, the race director, when he announced the decision.
In a statement the UCI said the Tour organisers had committed a technical error over the time periods set down in the body's rules. "The disciplinary commission ordered the organisers to readmit the riders to the competition in question," the statement said.
Virenque, who has won the King of the Mountains title three times, was a member of the Festina squad which was embroiled by a drugs controversy during last year's Tour. While several of his Festina colleagues admitted to drug usage, Virenque has always denied knowingly taking banned substances.
French authorities have placed Virenque and his former team-mates Laurent Roux and Philippe Gaumont under formal investigation, a step away from being formally charged. The Tour de France starts this weekend.
Elsewhere, prosecutors in Florence have formally notified officials of three Italian teams that they are under investigation for allegedly giving athletes banned drugs.
Police were also reported to be searching the homes of dozens of cycling officials and athletes, including Ivan Gotti, this year's Tour of Italy winner, and Pavel Tonkov. Prosecutors gave notifications to sports directors Sandro Lerici, of the Vini Caldirola team; Fabio Bordonali, of the Liquigas team; and Pietro Algeri and Mauriio Piovani, of the Lampre-Daikin team. Notifications were also given to Daniele Misseri, the masseur for Vini Caldirola and Andrea Conti, the team's mechanic.
The action came only days after the Swiss television programme Sport Aktuell said one of its reporters saw someone from the Lampre team dispose of banned drugs and syringes during the Tour de Switzerland. Lampre is led by the world champion Oscar Camenzind, who was a stage winner and finished fifth overall in the Swiss event, and also includes the Italian Gabriele Missaglia, a former leader of the race.Reuse content