Borussia Dortmund chief executive Hans-Joachim Watzke feels clubs like Manchester City should be "expelled" by UEFA.

As the reigning Bundesliga champions continue to work to a strict budget and are 51 per cent owned by the club's supporters, a number of their continental rivals are taking advantage of what Watzke considers to be "back-door funding".

Manchester City, who Dortmund face in the Champions League on Wednesday, are among those to have benefited greatly from the arrival of a wealthy owner with useful contacts.

The 2011/12 Premier League winners have been able to sign a lucrative £350million stadium and shirt sponsorship deal with Etihad, a company connected to their owners.

Watzke believes such deals are unfair, in an era where financial fair play is supposedly the way forward, and he has called on the authorities to clamp down on big-spending figureheads.

"UEFA must find the thin line between sponsorship and excessive back-door funding - they must show strength to expel big clubs," he said.

"No tycoon should be allowed to pump crazy money into a club with sponsorship from five companies he controls. If that happens, financial fair play will fail.

"I would not even welcome him (City owner Sheikh Mansour). What if the sheikh, as shown by Malaga , lost interest?"