Chinese swimming is being investigated over claims that five positive drugs tests were covered up.

Whistleblowers within Chinese swimming approached The Times­ alleging that five tests had been hidden to avoid a storm before the Olympic trials next month and asked the ­newspaper to pass the information to the World Anti-Doping Agency (Wada), which is now investigating. Two of the tests are believed to have been failed in October and the other three at the turn of the year.

The revelations come as Fina, ­swimming’s governing body, and Wada vowed to investigate yesterday’s revelations by The Times concerning the ­extent of doping in Russian swimming. Rebecca Adlington, Britain’s double Olympic ­champion, welcomed the inquiry and urged the sport to launch “a full-on ­investigation” so that swimmers could arrive at the Olympic Games in Rio de Janeiro confident that they were not ­racing against cheats.

The Chinese whistleblowers, who were unable to contact Wada because of state surveillance, are desperate for outside help, with one intermediary of a source saying: “People in Chinese swimming really want Wada to ask for the truth to be told. Our pools are awash with rumours of bad things. There’s a lot of fear.”

The news comes amid reports in China, who came second in the swimming medals table at London 2012, that one of the biggest rogues in swimming history is playing an increasingly ­influential role in the sport.

Zhou Ming, a mastermind of the 1990s China crisis, when more than 45 teenagers tested positive, mostly for banned substances in the highest category of offence, is said to have been working with swimmers in Tianjin.

His presence has sparked questions in China such as that sent to The Times: “What is the Chinese Swimming ­Association doing about it? The ­Chinese Swimming Association must know about the rumours running through the sport here.”

Ming is not officially connected to the national programme these days but his name raises concern inside China and beyond.

He was one of the head coaches to the 1990s squad of teenagers fed a diet of steroids, diuretics and other banned substances and was banned for life by the Chinese and the world governing body in 1998 during the World Championships. That was after some of his swimmers tested positive on the eve of competition and in the wake of customs officers seizing 13 vials of human growth hormone from the kitbag of an athlete when the China team passed through Sydney airport.

When Ming reappeared poolside in China in 2005, the Chinese Swimming Association responded to questions about his lifetime ban with a statement that his suspension period had not been life but “eight years”. That would have meant a 2006 return at the earliest. The Times has put several questions to Ming, via the Chinese Swimming ­Association, and further questions to Zhang Qiuping, China’s member of ­Fina, but has received no reply.

When alerted tothe investigation by The Times, the boards of the World Swimming Coaches Association (WSCA) and American Swimming Coaches Association (ASCA) said: “We call on Wada to extend its inquiries to all nations sounding the kind of alarm bells we hear tolling from the likes of Russia and China. Zhou Ming is a name well known to coaches who lived through the crisis of the 1990s. He is a rogue who ought never to be allowed to work with children.”

Those in Chinese swimming crying out for Wada’s intervention do so at a time of heightened sensitivity. Last ­November, the sport in China was rocked by the death of Qing Wenyi, 17.

I just want everyone to be tested equally. I get tested a lot

Less than three weeks after she claimed both girls’ breaststroke titles at the China Youth Games, she collapsed and died at a national-team camp in Beijing.

News of Qing’s death prompted Anne Tiivas, the head of the child ­protection in sport unit at the NSPCC in Britain, to tweet: “Such a tragic death. When will current attention focus on the well-being of young talented and elite athletes?”

There are also concerns in Australia, where many Chinese swimmers train, about how often drugs tests are being carried out. Grant Hackett, the ­Olympic 1,500 metres freestyle champion in 2000 and 2004, who is on the comeback trail, said that he ­believed some of the Chinese training in Australia had been approached for a sample once in 18 months — and then only because Swimming Australia pressed the matter.

“That’s all I have witnessed,” he said. “I don’t know if there are people going to their hotel. I just want everyone to be tested equally. I get tested a lot.”

Swimming Australia imposed new rules a year ago ­forbidding any ­swimmer who has failed a drugs test from training at the centre of ­excellence in Miami, Queensland, after a ban for Sun Yang, the Asian champion over 1,500 metres, in 2014.

Working with Chinese swimmers can be very lucrative for Australia, with about 100 Chinese swimmers still based for at least part of every season on the Gold Coast. But Bill Sweetenham, the veteran Australian coach and former head coach of Britain, described the practice of taking in “Chinese drug cheats” in some swimming centres as, “wholly unacceptable”.

“What does it say about your morals, your ethics, the choices you will make?” he asked last autumn. “I hear all the ­arguments about ‘they need the money’. We all get that,” Sweetenham said. “But why would you want to take on responsibility for people who have fallen foul of doping rules? China’s problems have become Australia’s problems.”