Sinkewitz denies leak

"I did not say anything concrete on the doping practices of others riders," Sinkewitz - currently serving a one-year ban for a failed drugs test - insisted to German tabloid Bild.

"I do not know where this information comes from," he added about an article in Saturday's Sueddeutsche Zeitung, which said Sinkewitz had passed on detailed information about team-mates including Andreas Kloeden and Matthias Kessler.

Kloeden, who finished second in the 2004 Tour de France, has threatened legal action over the allegations.

Kessler, a former T-Mobile rider until 2007, was sacked by Astana last July for a positive drugs test for abnormally high levels of testosterone.

Sinkewitz himself was sacked by T-Mobile in July 2007 after a positive drugs test.

To have his ban reduced to one year, Sinkewitz has been passing on working with investigating officers to give information about his former team, especially around the 2006 Tour de France.

The winner of 2004 Tour of Germany revealed to Bild he had lost around one million euros through lost earnings and sponsorship contracts since his fall from grace.

The 27-year-old is trying to find a new team for July 2008 when his ban finishes.

"I train daily for up to five hours per day, I want to show that I can be powerful," he insisted.