Fourteen-time Grand Slam champion Rafael Nadal asked for the results of all drugs tests he has taken in his career to be released to the public in a letter to the International Tennis Federation (ITF) on Tuesday.

Nadal filed a lawsuit against former French sports minister Roselyne Bachelot on Monday after she accused him of covering up a failed drugs test.

"It is necessary that our sport becomes a flagship in a world where TRANSPARENCY and HONESTY are two pillars of our conduct and way of living," Nadal wrote in the letter addressed to ITF president David Haggerty.

Bachelot alleged that Nadal -- one of Spain's most loved and admired sportsmen -- faked an injury in 2012, when he missed the final six months of the season due to knee problems, in order to hide a positive drug test.

Nadal has never failed a drug test in his many years on the ATP Tour and has always vehemently denied ever using a banned substance.

"I believe the time has arrived and our sport and our governing bodies need to step up in communicating well to the world," Nadal's letter continued.

"I know how many times I am tested, on and off competition. Please make all my information public. Please make public my biological passport, my complete history of Anti-Doping controls and tests.

"From now on I ask you to communicate when I am tested and the results as soon as they are ready from your labs.

"I also encourage you to start filing lawsuits if there is any misinformation spread by anyone. It can't be free anymore in our tennis world to speak and to accuse without evidence."

ITF response

The ITF acknowledged receipt of Nadal's letter and confirmed he had never committed a doping violation, while inviting the Spaniard to personally make his records public.

"The ITF has received a letter from Rafael Nadal that includes a request to release his personal test results under the Tennis Anti-Doping Programme (TADP)," the federation said in a statement.

"The ITF can confirm that Mr. Nadal has never failed a test under the TADP and has not been suspended at any time for an anti-doping rule violation (or for any other reason related to the TADP).

"Mr. Nadal, as all other players who are subject to the TADP, has access to his anti-doping records through WADA's ADAMS database and is free to make them available. The accuracy of any such release would be verified by the ITF," it added.

The spectre of doping in tennis has drawn increased attention in recent months after five-time Grand Slam champion Maria Sharapova admitted she failed a test for the banned substance meldonium at this year's Australian Open.

One of Nadal's leading rivals on the ATP Tour, Britain's Andy Murray, has been a vocal critic of the need for the tennis authorities to do more to protect the sport from doping.

Murray even went as far in a recent interview with the Daily Mail as to say he had been suspicious of opponents who he thought were not tiring as they ought to in matches.

However, those comments were criticised by six-time Grand Slam winner Boris Becker, who is now the coach of world number one Novak Djokovic.

Becker said Murray was "out of order" in making his feelings known without proof.

"I believe 100 percent Andy is clean. Roger (Federer) is clean, Rafa is clean, all these guys are clean," said Becker.