UEFA has insisted its Financial Fair Play (FFP) regulations have been introduced to make the game more sustainable and not to force financial equality after a top lawyer questioned its legality.
Jean-Louis Dupont, one of the leading football lawyers and part of the legal team which represented Jean-Marc Bosman in 1995 which resulted in players being able to leave clubs as free agents at the end of their contracts, believes FFP could be in tatters if it is challenged in the courts.
The European Commission has approved FFP, but there is still the possibility that European competition laws could be used to invalidate the new regulations.
A UEFA spokesman said: "UEFA is aware, that there are large differences between the comparative wealth of different clubs and countries, but financial fair play does not have financial equality as its objective.
"However, more investors should be attracted if club football is more sustainable and those clubs with sustainable and stable business models will be in a position to become more competitive.''
Dupont, writing a column in the Wall Street Journal, had said: "Some of Europe's biggest clubs are, unsurprisingly, the loudest supporters of rules that entrench their dominance. The time is right for a strong reminder from the EU's anti-trust authorities that football, like any other multibillion-euro industry, must comply with the law.
"As an agreement whereby industry participants jointly decide to limit investments, FFP likely constitutes collusion and hence a violation of EU competition law. FFP may also infringe other EU freedoms such as the free movement of workers and services.
"Even if FFP were sufficiently legitimate and necessary to justify its distortions of EU principles, however, it would still have to clear a final hurdle: proportionality. UEFA would need to convince the EU's judges in Luxembourg that FFP is the least restrictive means of achieving its aims. This seems unlikely.''
Information from the Press Association was used in this report