Cycling teams Festina and TVM, entangled in the Tour de France doping scandal, are eligible for this year's race despite the furore of 1998.
The Societe du Tour de France issued a preliminary list yesterday of 16 teams based on International Cycling Union rankings, although organisers stressed changes were possible right up until the start of the race and beyond.
"We didn't have any reasons to drop either Festina or TVM," a Societe spokesman said. "Investigations are under way but they are presumed to be innocent.
"If it turns out that riders are guilty of cheating or if they don't abide by our new regulations, we will be merciless," he added.
The trial of Festina, in which former team manager Bruno Roussel and masseur Willy Voet have been indicted for importing banned substances, is not due to begin until October.
Festina were kicked out of last year's Tour after Roussel confessed to an "organised doping system," although team leader Richard Virenque has insisted he never knowingly took any performance-enhancing substances.
Virenque considered retiring but is now set to make his debut with the Italian team Polti in the Paris-Nice next month.
The Societe spokesman said: "It's not proved Virenque is guilty and as far as we are concerned we can't judge him.
"He belongs to a team which is eligible according to our usual criteria and it sounds logical to have him in the race."
But he pointed out: We can bar a team from entering the race until the very last minute and we can drop them even after the race has started."
At the unveiling of the itinerary last October, Societe president Jean-Marie Leblanc said new regulations would be implemented so they could exclude any team or rider who did not show "the required respect for the morality of the sport."