The German football association, DFB, on Saturday rejected allegations surrounding a fund which was reportedly used to secure votes to host the 2006 FIFA World Cup.
German news weekly Der Spiegel said that 6.7 million euros came in as funds from late former Adidas boss Robert Louis-Dreyfus.
FIFA said in a statement the "serious allegations" would be investigated while the DFB plans legal action. Germany had clinched the votes 12:11 against South Africa, who hosted the quadrennial extravaganza four years later.
"The DFB categorically rejects the baseless allegations by the publication that the association had paid illicit funds in relation to the 2006 World Cup," BBC quoted a statement from the German FA.
"The association also rejects the completely unsubstantiated conclusions that these funds were used to buy votes in exchange for the World Cup."
FIFA said in a statement: "These are very serious allegations that will be reviewed as part of the independent internal investigation currently being conducted by FIFA under the direction of its legal director with the assistance of outside counsel."
The news weekly also believes that the huge amount of money was later paid back to Dreyfus in 2005 through FIFA.
Reportedly the 2006 World Cup organising committee made a 6.7 million euros contribution for a gala opening ceremony at Berlin's Olympic Stadium. But this money was later withdrawn.
The publication alleges the money was then paid into a FIFA bank account in Geneva and from there transferred to a Zurich account belonging to Dreyfus, who has since died.
World Cup organising committee president and 1974 World Cup-winning captain Franz Beckenbauer and German FA president Wolfgang Niersbach knew about the fund by 2005, claimed Der Spiegel, but the German FA denied such an allegation.
Beckenbauer and Niersbach have not personally responded to the accusations.