US cyclist Lance Armstrong will make his official comeback to professional road racing in January at the Tour Down Under in Australia, organizers of the Adelaide stage race said Wednesday.

Armstrong announced his retirement after winning the Tour de France a record seven times in 2005 but has said he would try for an eighth triumph in the world's most prestigious road race.

He is due to announce more details of his return at a press conference in New York later Wednesday amid reports he is set to join Astana.

At Astana he would team up again with his former race director Johan Bruyneel, who guided him to all his Tour de France victories.

The Kazakh-financed Astana team, now based in Switzerland, suffered two high-profile doping scandals in 2007 and were excluded from this year's Tour de France but has now started afresh under new management.

Current team leader Alberto Contador, who has just won the Tour of Spain to add to this year's Giro d'Italia and the 2007 Tour de France titles, has already indicated Armstrong's presence could cause difficulties.

"I've earned the right to be the leader of a team without having to fight for my place," Contador told Spain's AS newspaper on Tuesday.

"And with Armstrong, some difficult situations could arise in which the team would put him first and that would hurt me."

The six-stage Tour Down Under, starting January 20, is the first major event of the 2009 professional cycling calendar and attracts some of the world's top teams.

Professional cyclists like it because it's a warm change from gruelling training in the Northern Hemisphere winter. The six-day race, won this year by up-and-coming German rider Andre Greipel, circles the picturesque Barossa Valley wine-growing region.

Past attempts to bring Armstrong to Australia have failed because of cost and scheduling issues.