Stuttgart is threatening to withhold 600,000 euros due to the International Cycling Union (UCI) because it believes the governing body has not done enough to combat doping at the world championships.

"We will not hand over taxpayers' money to any organisation that is not fighting seriously against doping," Mayor Wolfgang Schuster told the Stuttgarter Nachrichten newspaper on Saturday.

According to the newspaper report, Stuttgart will also withhold 75,000 euros ($106,000) from the German Cycling Federation.

The money is due in Stuttgart's contract to host the world championships, which end on Sunday, and UCI President Pat McQuaid said on Saturday his organisation would use all legal means to collect any outstanding money.

"It's been reported that Stuttgart is refusing to pay the third and final instalment in the contract with the UCI and I think we can take that as a statement coming from the city," McQuaid said at a news conference.

"We have a legal contract and we expect it to be adhered to. We'll take whatever steps we can to make sure it is."

McQuaid would not confirm the amount of money but described it as a significant sum and that it would hurt the UCI.

Stuttgart is unhappy the UCI is allowing riders who have not signed its anti-doping pledge to start in the event.

The city filed for an injunction to stop defending world champion Paolo Bettini, who has not signed the declaration, from participating but a court rejected the request on Friday.

Earlier this week McQuaid accused Stuttgart sports commissioner Susanne Eisenmann of hijacking the world championships for political reasons.

The UCI president warned the city that the events of the week would hurt its chances of hosting future sporting events.