Niermann admits to doping

German cyclist Grischa Niermann has admitted to using performance enhancing drugs during his professional career.

The announcement comes in the wake of news that the 'Operation Puerto' case, which hopes to expose an international doping network, would start in Spain on Monday.

The 37-year-old Niermann, who used to ride for Dutch team Rabobank, said he would be prepared to give anti-doping authorities any information they needed to help eradicate the problem, which has plagued the sport for years.

"I will give anti-doping bodies and relevant commissions all further information," Niermann toldwww.knwu.nl.

The cyclist reportedly admitted to using the banned substance EPO several times between 2000-2003.

"I went through hell and back the last few weeks, but I decided that this is the only possible way to go for me," said Niermann, who competed in nine editions of the Tour de France.

Niermann is the latest of several German cyclists to have used banned substances.

Jan Ullrich, also a former Tour de France champion and three-time runner-up to the disgraced Lance Armstrong, was found guilty of doping by the Court of Arbitration for Sport (CAS) last year.

Ullrich was subsequently banned from the sport for two years. All his results between 2005-2011 have been annulled.

Former Rabobank rider, Thomas Dekker, was also suspended for doping in 2009.

Meanwhile he has also indicated he was prepared to assist authorities with information.