Bruno Ravaz's comments came after L'Equipe sports daily ran a report saying the 52-year-old Longo broke the rules twice in the past 18 months and then again a third time on June 20, while training in the United States.
As a result of the three violations, Lungo is expected to be brought before France's cycling federation, where she faces a suspension of three months to two years.
A lengthy ban could spell the effective end to one of French sport's longest and most brilliant careers. Longo first competed in the Olympics in 1984 in Los Angeles and won the gold medal in the road race at the 1996 Atlanta Games. She has nine road world championship golds, claimed four titles at the world track championships and has been French champion 58 times.
A French official confirmed the Equipe report, though he said Longo missed two drug tests, not one. The official, who was not authorized to speak publicly on the matter and spoke to The Associated Press on condition of anonymity, said one no-show was in France, when Longo was not where she said she would be when testers went to find her.
The other no-show was in the U.S., as L'Equipe indicated, the official said. The third case was not a no-show but rather Longo failing to properly complete the requirements that athletes keep anti-doping agencies informed of their whereabouts, the official said.
The official did not say whether Longo would now face disciplinary action. The French anti-doping agency said it would not comment.
Ravaz explained away the three violations, saying a strike at French gas stations kept her from getting to where she was expected on one occasion.
The second violation occurred when "the person in charge of administering the test couldn't find her father's chalet in Saint-Gervais," France, Ravaz said, adding that "in between, she passed tests."
"She received a third warning following a test that strangely happened on her last day in the United States just as she was coming back to France the following day to take part in a race," Ravaz said.
Ravaz added that Longo would attend any future disciplinary hearing, although she has not yet been summoned.
Longo's home phone rang unanswered Friday morning and she did not immediately respond to an email seeking comment.
In an AP interview in February, Longo's response was ambiguous when asked whether doping might be part of her longevity in cycling. Instead of a flat "no," she launched into an explanation of how there are no level playing fields in sports "because we all do what we can to be better."
She complained that the anti-doping controls to which elite athletes are subjected are "lamentable, unforgivable" and noted there are cheats in the finance world, too.
"Nine-tenths of the population take antibiotics, antidepressants, pain tablets and whatnot and athletes who do no harm to anyone are pestered," she said. She says she eats organic food and is supersensitive to pollutants, even perfumes.
Longo has been scheduled to compete in the upcoming world road cycling championships in Copenhagen, Denmark, from Sept. 21-25.
AP Sports Writer John Leicester contributed to this report.