The American’s team, Phonak, revealed on Thursday that Landis had failed a test after stage 17 of the event, but he insists the result was “absolutely natural”.
“We will explain to the world why this is not a doping case but a natural occurrence,” Landis told a news conference in Madrid.
“The level is absolutely natural and produced by my own organism.
“I will continue to undergo all relevant tests to prove my innocence. I want it (the B sample result) to be made public immediately, I see no reason why not.”
The 30-year-old won the stage in question, from Saint-Jean-de-Maurienne to Morzine-Avoriaz, by almost six minutes after seemingly dropping out of contention for victory the previous day.
But he insisted the timing of the result was not significant.
“I was tested six other times during the Tour,” he said. “Where it came up, I don’t know what relevance that has.
“I’m quite proud of that day. I was the strongest guy and I deserved to win.”
If Landis’ B sample also tests positive, he faces potentially being stripped of his title, but he maintains he was a worthy winner.
“When I heard (the result) I was surprised and disappointed that this process would begin, but I’m proud that I won the Tour because I was the strongest guy there,” he said.
“I declare convincingly and categorically that my winning the Tour de France has been exclusively due to many years of training and my complete devotion to cycling.”