China remains the "major source of supply" for illegal performance-enhancing drugs, according to World Anti-Doping Agency (Wada) president John Fahey.
His comments came after Wada director-general David Howman said on Tuesday that "99 per cent of illegal substances come from China".
Howman added the "same bad guys" were involved in both match-fixing and the supply of illegal drugs because of the huge sums of money involved in each area.
Fahey said progress had been made with Beijing authorities but that more needed to be done.
"On numerous occasions we've made representations to Chinada [China's anti-doping agency]," Fahey said. "I've had discussions with the sports minister and I'm conscious of certain action being taken.
"We've certainly asked for their co-operation and we are conscious of many suppliers being shut down as a result of our representations in the past.
"That's not to say it still isn't the major source of supply - we know it is."
Wada's effectiveness was called into question by Swiss-based UNI Sport PRO, an umbrella group of national and international sporting associations, who slammed its handling of the Lance Armstrong scandal.
The disgraced American cyclist, who recently admitted to being a serial drugs cheat, was banned for life and stripped of his seven Tour de France victories following an investigation by the United States Anti-Doping Agency (Usada).
Last week, meanwhile, an Australian Crime Commission report said use of prohibited products was common across multiple sporting codes, sending shock waves through Australia - a country where sport has a central role in national life.
"Regrettably, the World Anti-Doping Agency and its stakeholders are failing in their mission to protect clean athletes," UNI Sport PRO said.
But Fahey insisted there was more to catching drugs cheats than dope tests and that there was no substitute for government action.
"We [Wada] have made some significant progress since our inception [in 1999]. We now have a methodology that is far smarter," he said. "Once upon a time it was test, test, test and if you do enough tests you'll pick up enough cheats. It's a waste of time just testing anybody. You need to test the likely cheats.
"We've got to use other methods to bring them under the [Wada] code. Possession or admissions and so on.
"All of that's happening because we are seeing many countries working with law-enforcement agencies and my own country [Australia] demonstrated that again last week. We can't see enough of that.
"But is the problem still as big as it ever was? There's no doubt it's still a massive problem."
Fahey's mandatory maximum six-year term as Wada president ends this year.
However Fahey, a former premier of New South Wales state and chairman of an inspectorate supervising the rebuilding of flood-damaged roads and bridges in Queensland, said he had no intention of returning to front-line Australian politics.
"I learnt long ago that you never go backwards," said Fahey, who also played a key role in Sydney's successful bid for the 2000 Olympic Games.
"I gave 18 years to politics and whilst I can say I enjoyed it, it's not something I wish to put my time into in the future, apart from the fact that if I even thought about it my wife would shoot me."