Matthew White on Saturday resigned as sports director of Team GreenEDGE and from his roles with Cycling Australia after admitting to illicit drug use when on Lance Armstrong's US Postal team between 2001 and 2003.
"I am sad to say that I was part of a team where doping formed part of the team's strategy, and I too was involved in that strategy," he said in a statement.
"My involvement is something I am not proud of and I sincerely apologise to my fans, media, family and friends who trusted me and also to other athletes in my era that consciously chose not to dope."
The US Anti-Doping Agency has urged the International Cycling Union to deprive Armstrong of his seven Tour de France titles after accusing him of doping.
White was named by Floyd Landis as one of the US Postal riders taking the blood booster EPO and the steroid testosterone.
GreenEDGE said in a statement that it welcomed White's departure.
"We hope for a quick and clear resolution of this issue and will await the decision of the relevant authorities," Australia's first professional cycling team said in a statement.