Nine Australian athletes have tested positive for banned stimulant methylhexaneamine and some of them could be from the Commonwealth Games squads.
The authorities have not revealed the identity of the athletes but they did not rule out CWG athletes as being among those who returned positive tests, a media report claimed.
"It is believed NRL and AFL players may have also been among those who tested positive in what could become Australia's biggest doping scandal," a report in the Daily Telegraph said.
According to the report, the testing period is believed to have covered this year's NRL and AFL grand finals and pre-and post-Commonwealth Games periods but not the 10 days of Games competition, which was covered by international anti-doping authorities.
The positive results prompted the Australian Sports Anti-Doping Authority to take the extraordinary measure of sending an urgent warning to all Australian athletes about inadvertent use of the substance.
"With the spike in the number of positive test results for methylhexaneamine in Australia, we are warning athletes to take extreme caution and double check the contents of any supplements and other products they use," ASADA CEO Aurora Andruska said.
Federal Sports Minister Mark Arbib has also urged athletes to take extra precautions.
"We are warning athletes to take extreme caution and double check the contents of any supplements they use," he was quoted as saying in the report.
Nigerian runner Osayomi Oludamola was tripped off her Commonwealth Games gold medal for testing positive for the same substance.