Disgraced cyclist Lance Armstrong was paid $1.5 million by the South Australian government to race at the Tour Down Under in 2009.
The amount was revealed after a 10-year agreement to keep it secret expired.
Armstrong raced at the 2009 Tour Down Under following his 2005 retirement and was paid in taxpayer money to do so, reports Australia's Sunday Mail.
The 47-year-old was not required to repay the money after admitting to taking performance enhancing drugs as the deal did not include a clause about doping, according to reports.
South Australia treasurer Rob Lucas said the agreement also reportedly included first-class flights, hotel accommodation and meals, on top of the appearance fee.
"Finally, we can reveal to South Australians what Labor MPs have been happily sitting on for a decade – that they forked-out a staggering US $1 million on behalf of taxpayers to an athlete who was subsequently exposed as the ringleader of the world's most sophisticated doping program in sporting history," Lucas said, according to reports in the Australian media.
"By anyone's standards, it's an astonishing amount of money to pay one man for a six-day race, not to mention the extra sweeteners on the side – first-class airfares for two, hotel accommodation, meals and other incidentals. And this is just the tip of the iceberg."
Armstrong was also paid to appear in the 2010 and 2011 editions of the race, but the figures have not been revealed yet. He eventually confessed to doping in 2013 after being banned from the sport for life.
Australia's Minister for Tourism and Minister for Sport said that Armstrong's participation in the Tour Down Under elevated the profile of the event.
"Lance Armstrong's appearance at the Santos Tour Down Under came at a time when he was considered the greatest cyclist in the world," Bignell said.
"He brought the eyes of the world with him to South Australia when he rode in the Tour Down Under, taking the race to a whole new level. The state government has continued to leverage this exposure, ensuring crowd numbers continued to climb even after Lance's final appearance."