The German FA (DFB) has vowed to take legal action against Der Spiegel over what it describes as "completely baseless" allegations over the voting for the 2006 World Cup.
FIFA has said it will investigate the allegations that Germany used a secret slush fund for bribes to buy votes to host the tournament.
German news weekly Der Spiegel has said it has documents detailing a €6.7 million fund set up using money provided by former Adidas chief executive Robert Louis-Dreyfus, acting in a private capacity.
Der Spiegel claims the money was later re-paid to Dreyfus in 2005 using FIFA as cover -- the German World Cup organising committee made a €6.7m contribution for a gala opening ceremony at Berlin's Olympic Stadium, which was later cancelled.
The publication says the money was then paid into a FIFA bank account in Geneva and from there transferred to a Zurich account belonging to Louis-Dreyfus, who has since died.
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."
Der Spiegel claims 2006 World Cup organising committee president Franz Beckenbauer and German FA president Wolfgang Niersbach -- who is also a UEFA and FIFA Executive Committee member -- were aware of the slush fund by 2005. Neither has personally responded to the claim.
The DFB had earlier said it was investigating whether the €6.7m "may potentially not have been used for the intended purpose" but stressed that there were "no indications at all" of delegates' votes being bought.
It later issued a strong statement saying it planned to take legal action over Der Spiegel's report.
The statement read: "The German football association (DFB) categorically the baseless allegations by the publication Der Spiegel that the association had paid illicit funds in relation to the 2006 World Cup.
"The association also rejects the author's completely unsubstantiated conclusions that these funds were used to buy votes in exchange for the World Cup. The DFB therefore states explicitly once more, that neither the DFB president, nor the other members of the organisational committee were involved in such transactions, or indeed could have had any knowledge of them.
"The DFB will be taking legal action against the claims made by the magazine Der Spiegel."
Niersbach insisted the German World Cup bid victory was entirely above board in an interview on the DFB website.
"I can rule that out categorically," said Niersbach, who admitted the allegations "hurt."
"I can assure that in relation to the bidding and awarding of the 2006 World Cup there were no 'slush funds' at the DFB, the bidding committee or the later organising committee. We were acknowledged at the time as the absolute best candidate and we won the vote 12-11 with our arguments for Germany as hosts.''