Adidas may stop sponsoring cycling after a new doping scandal hit the Tour de France, the sport's most prestigious race, the German sports goods maker said.

"We are currently looking into and seriously considering an exit of our sponsoring activities connected with cycling," a spokeswoman said.

T-Mobile rider Patrik Sinkewitz tested positive for elevated levels of testosterone during a training camp, Germany's cycling federation said last week, the latest headache for the Tour which is trying to clean its record of doping scandals.

Sinkewitz has agreed to undergo a B test which could confirm or remove suspicions that he may have violated doping rules.

T-Mobile have suspended the Sinkewitz, who withdrew from the Tour after being injured in a collision with a spectator after last Sunday's eighth stage, and said they would cancel his contract if he failed the B test, results of which are expected this week.

Car-maker Audi might also withdraw its support for the sport, German media reported.

Adidas spent roughly half a million euros ($690,400) a year on the T-Mobile team and also supported the German and French federations, the report said. Adidas would not elaborate on how much it spent on cycling.

Deutsche Telekom will decide on whether it will continue to sponsor T-Mobile after the Tour.

German cycling has been hit by a string of doping confessions, including admissions by former Telekom riders Bjarne Riis from Denmark and German Erik Zabel that they used banned substances in the 1990s.

German broadcasters ARD and ZDF have halted coverage of the Tour since the Sinkewitz scandal.