Lance Armstrong wrapped up his international career in low-key fashion yesterday, and then left without answering reporters' questions about lingering doping allegations.

The 39-year-old American finished his last professional international race 65th overall, almost six minutes adrift of race winner Cameron Meyer of Australia.

After accepting an award on stage for his support of the race, Armstrong brushed past reporters and was driven away in a team car.

His exit from international cycling came in the backdrop of comments made by his former mechanic Mike Adams, who told a New Zealand newspaper that an American federal investigation into Armstrong's alleged involvement in doping could make him a "symbol for decades of corruption" in the sport.

The Texan, who never tested positive throughout his career, has denied any wrongdoing and said on Friday he was keen to cooperate with the US Anti-Doping Agency following fresh doping allegations published by Sports Illustrated. He is set to make a few international appearances throughout the year but will not be riding as a professional.

Team manager Johan Bruyneel, however, said Armstrong could ride a last pro race in the US at the Tour of California in May.

"@tourdownunder is done. Thanks to everyone for coming out and supporting such a great race. #Adelaide, we're gonna miss ya," he wrote on Twitter after the sixth and final stage was won by Briton Ben Swift, who led a Team Sky one-two with New Zealand's Greg Henderson.

"I was struggling about half way through the stage after my efforts on Willunga Hill yesterday but my team did an absolutely perfect job for me," Swift said. "It was straight out of the book of how to do a lead-out and all I had to do then was finish it off."

Garmin Cervelo rider Meyer held off Australian compatriot Matt Goss by two seconds to win the race, with his nearest challenger eating into his overnight eight-second advantage but unable to overhaul the leader.