The country's Sports Ministry confirmed no anti-doping tests were carried out between July 1 and July 24, a move described by WADA as "unacceptable".

Brazil claimed the decision was made after WADA suspended its testing laboratory in Rio de Janeiro in June.

The suspension was subsequently lifted which led to WADA questioning why the second largest team at these Olympics was not being properly monitored at such a "crucial time".

A senior official, Luis Horta, has claimed he left his role with Brazilian Doping Control Authority (ABCD) after being put under pressure by the Brazilian Olympic Committee, led by Rio 2016 President Carlos Nuzman, to reduce testing in the build-up to the Olympics. 

"We sent a letter to the Minister of Sport and the executive director of the Brazilian national anti-doping agency, pressing our concerns and demanding to know why testing had been stopped," Rob Koehler, WADA's deputy director general, told The Times in London.

"The response was not satisfactory - the explanation that it had come about due to the changing of the guard in the Ministry and the Agency was not acceptable to us.

"It was unacceptable that it stopped. 

"That was not a good move - the fact no testing was happening was a concern."

"At a time when the integrity of sport is on the line, it is vital that effective, rigorous testing is in place across the world so that the athletes and public have full confidence in sport."

Horta claimed the ABCD had planned to conduct 300 random tests before Rio 2016 but came under pressure to ease back. 

"In June the Sports Ministry and the Olympic Committee were putting pressure on us, saying we were making too many doping controls on the athletes and this was causing a problem for their training," he said.

"We were performing around three a year and in some cases on the best athletes as many as six in the last year.

"They also said we were too strict in the employment of the whereabouts system.

"The Anti-Doping Agency's primary objective was for many medals and all of them clean, [but some parties] just wanted many medals, whether clean or not."

Mario Andrada, director of communications at Rio 2016, today denied Nuzman had put anu pressure on Horta.

"The President of the Brazil NOC has reiterated today his commitment to zero tolerance for any case of doping or missing tests," he said.

International Olympic Committee (IOC) spokesman Mark Adams revealed they had no plans to investigate the claims.

"As you know there is a lot of pre-competition testing going on, we are very confident the Brazilian athletes have been properly tested thanks to the testing programme of the IOC and the International Federations," he said.

"We don't actually see it as an issue."