Wallaby winger Ben Tune was given a banned substance last year and the Australian Rugby Union did not inform the International Rugby Board after it became aware of the situation.

A report in the Courier-Mail newspaper outlines the circumstances which saw Tune withdrawn from four Queensland Reds Super 12 matches as the banned masking agent probenecid remained in his system.

According to the report, Tune was prescribed penicillin and then probenecid while spending a night in hospital for an infected knee in mid-March last year.

He subsequently played two Super 12 matches before officials discovered that probenecid is on the IRB's list of banned substances.

The IRB charter states that a player caught with probenecid in his system faces a mandatory two year ban.

Tune was then withdrawn prior to the next four Reds Super 12 matches while the Queensland Rugby Union (QRU) ran secret testing on his urine at a Sydney laboratory.

The tests showed traces of probenecid and officials did not want to risk him being tested by the Australian Sports Drug Agency (ASDA), which tests two or three players after each game.

The Courier-Mail quoted QRU chief executive officer Jeff Miller as confirming that Tune was administered probenecid on March 19 last year.

"The decision to rest him from four Super 12 matches was made weekly, based on both the level of infection still in the body and the risk of a positive drug test," Miller said.

"The media were truthfully advised that Tune was still suffering from the infection."

Like any other person, Tune had the right to have his medical details remain confidential and the media was only told part of the story to protect the player's privacy, Miller said.

"There was no cover-up. Both ASDA and the ARU were advised fully of the situation."

His treating physician, Dr Peter Myers said the drug probenecid was on a "notification list" and that he had notified the ASDA only to find later it was banned by the IRB and carried a mandatory suspension.

"There was concern whether he should get back on the field and risk being tested," Dr Myers said.