"One can't not envisage it," Leblanc told journalists in Paris. "We would understand if there were an intervention by police, by customs agents, during the Tour, if it is necessary."
The 2004 Tour de France begins Saturday in Liege, Belgium. In the run-up to the race, a long-running investigation into the use and trafficking of banned substances has led to the barring of several riders from the Tour, including world time-trial champion David Millar.
Leblanc went on to say that, if a police intervention occurs, it must be carried out "with the greatest possible respect and dignity for these athletes, who will be going through three weeks of gruelling competition."
Past police raids on other cycling races, such as the Giro d'Italia, have led to the discovery of banned drugs in the possession of riders and their teams.
In this year's Tour, American Lance Armstrong will attempt to become the first rider to win the race six times.