Australian athletes hoping to compete at this year's Beijing Olympics have had their medical records secretly investigated by doping authorities.

The Australian Sports Anti-Doping Authority (ASADA) said the investigations were carried out without the permission or knowledge of the athletes.

ASADA Chairman Richard Ings said the probe, which was conducted with the national health scheme Medicare, was looking at what prescription drugs athletes might be using.

Ings did not provide details on how many athletes had been checked or whether anyone had been caught using performance-enhancing drugs but said the investigation was part of a trial aimed at uncovering cheating.

"ASADA was established specifically to be able to share information with other government bodies to be able to facilitate investigations into doping by Australian athletes," Ings said.

"We have just embarked on a trial with Medicare to determine if PBS (Pharmaceutical Benefits Scheme) records may have any evidence of possible doping by Australian athletes."

ASADA's actions drew criticism from various organisations in Australia, including doping officials and civil rights groups, which said the secret investigation was a breach of privacy.

"It concerns me a little bit that they're trying to treat all athletes with the same brush," Nicki Vance, the program manager for Doping Control at the Sydney Olympics, said.

"By going through records in what would appear to be just by the very virtue of being an athlete, we may be starting to really go over the top."

Ings said ASADA had conducted thorough legal checks before deciding to provide information about athletes to other agencies.

"We firstly review our legislation to ensure we can only share what we are able to share," Ings said.

"We also review the Privacy Act to determine what we are able to share and we seek independent legal advice from the Australian government solicitor before we make any moves to provide athlete information to other organisations."

Reuters