PARIS (Reuters) - The world athletics body (Iaaf) on Wednesday denied that it had any prior knowledge or evidence of Italian 2008 Olympic race walk champion Alex Schwazer's doping practices before he was caught with a positive test last year.

Schwazer, who was one of Italy's big medal hopes, was excluded from last year's London Olympics after testing positive for the banned blood-boosting substance EPO days before the start of the Games.

He was banned for three-and-a-half years by Italian authorities earlier this year.

"The Iaaf is aware of and shocked by the accusations made against it in (the) New York Times concerning the ongoing investigation in Italy regarding the case of the sanctioned Italian race walker Alex Schwazer," the body said in response to an article published on Tuesday.

The newspaper said that the Iaaf had evidence of Schwazer using banned substances but did nothing to stop him from going to London until a test conducted by the World Anti-Doping Agency (Wada) turned out positive.