The head of the French anti-doping agency (AFLD) has questioned the credibility of the testing due to be done during this year's Tour de France.
Pierre Bordry told the BBC that an international team of observers was being brought in.
This follows concerns over the way anti-doping was being handled by cycling's governing body, the International Cycling Union (UCI).
The AFLD has been prevented from carrying out extra tests this year.
Mr Bordry questioned the transparency of the UCI and said he had serious concerns about the biological passport for cyclists, the latest weapon in the fight against doping.
But the UCI says the decision to exclude the French was made by the World Anti-Doping Agency who fully endorse their testing programme.
In last year's tour, responsibility for anti-doping was shared between the UCI and the AFLD.
It was not a happy marriage. Afterwards the French complained that some riders, including Lance Armstrong and the winner Alberto Contador were given preferential treatment when it came to surprise tests.
This year the AFLD has been excluded from direct participation in the testing process.
Mr Bordry suggests that his agency's targeted testing, based on customs information and enforced by French police, is a more effective weapon than simply screening samples.
Mr Bordry says that the presence of international observers from the World Anti-Doping Agency, Wada, highlights his concerns.
"I think if this year there are three people from Wada to control UCI, surely there is a reason for that?" he said.
"If there was no problem last year, there wouldn't be any people from Wada as observers? If the UCI system was credible there wouldn't be any people from Wada. So we will see if it becomes credible with Wada people."
Mr Bordry also says the recently introduced biological passport is flawed.
The passport works by establishing a biological profile of riders.
Professional cyclists give samples of blood and urine several times a year.
Any deviation from their normal values is taken as an indication of doping even if the exact substance isn't known.
But Mr Bordry says cyclists can get around it by consistently taking small amounts of doping substances.
"I have no information about the blood passport from the UCI, I have information from some cyclists like Bernard Kohl saying some cyclists can do what they like with the passport, so if they have the same profile all the year, if they are doped all the year, they have a good passport," Mr Bordry said.
"The passport is not a good organisation for anti doping. I don't believe in the blood passport as it is done now."
The UCI rejects the accusations and says the decision to exclude the AFLD from this year's tour was made by the World Anti-Doping Agency.
The governing body says its testing is rigorous and effective and they will do their best to protect cycling, to protect the tour and to reduce the risk of any doping offence.
Their spokesman Enrico Carpani also defended the biological passport.
"We have created the most sophisticated tool that many other international sports organisation would like to introduce," he said.
"We are explaining, we are selling the biological passport to other federations so that's proof that this new approach is the most important and the most reliable that sport has today to fight against doping."
So bad have relations between the two organisations become that Mr Bordry is refusing to let his scientists work with the UCI on new methods of catching dopers.
"I won't work with UCI - I don't want to work with UCI," he said.
"We work with a lot of doctors and specialists all over the world, so we have no international problem but we don't want to work with the UCI on these projects, because they are not scientific people."