German football association President Wolfgang Niersbach has resigned over a 2006 World Cup scandal that has tarnished the reputation of the world's biggest soccer federation.

Niersbach, who is being investigated for tax evasion in relation to the affair, said he was taking the political responsibility for a controversial 6.7 million euro ($7.22m) payment to FIFA that was allegedly used to bribe officials of world football's governing body to vote for Germany's World Cup bid.

He again denied any wrongdoing.

"In order to protect the DFB and the position, I step down as DFB president with a heavy heart," Niersbach told reporters. "I decided to resign because I realised I had to take the political responsibility."

At the heart of the investigation is the 6.7 million euro payment from the DFB to FIFA in 2005 that Der Spiegel magazine alleged was a return on a loan from the then Adidas CEO Robert-Louis Dreyfus to help buy votes for Germany's World Cup bid at the FIFA election in 2000.

"I was there from the first day of the bid for the 2006 World Cup until the end ... and in all these years I worked not only in a clean way, but also with passion and trust," Niersbach later said in a statement issued through the DFB.

He had been at the DFB for a quarter of a century, climbing up from spokesman to general secretary and then president in 2012.

"That makes it even more depressing and painful to be confronted nine years later with processes I had nothing to do with. I want to make it clear once more that I was not aware of the payments in question. That's what makes the decision to suffer the political consequence so much harder."

Source: Reuters