Uefa has warned ministers that England could be excluded from the European Championship it is co-hosting in 2028 over "concerns" that a planned independent football regulator could lead to "government interference" in the sport.
A bill to establish a body to oversee the top five tiers of the men's game in England was reintroduced in July.
The UK government has said the football watchdog will "protect clubs" by "ensuring their financial sustainability".
But in a letter sent to Culture Secretary Lisa Nandy and seen by BBC Sport, Uefa general secretary Theodore Theodoridis wrote: "We do have concerns remaining... as normally football regulation should be managed by the national federation.
"One particular area of concern stems from one of Uefa's fundamental requirements, which is that there should be no government interference in the running of football.
"We have specific rules that guard against this in order to guarantee the autonomy of sport and fairness of sporting competition; the ultimate sanction for which would be excluding the federation from Uefa and teams from competition."
The FA's exclusion from Uefa could also prevent English clubs from competing in European competitions. But a Uefa source suggested that officials did not expect it to reach that stage.
The previous government announced plans to appoint a regulator last year following a fan-led review, which said such a body was necessary for the long-term financial stability of the men's professional game after issues including mismanagement and plans for a breakaway European Super League.
The regulator will oversee a licensing system to ensure clubs are run sustainably, take over a strengthened owners and directors test, and give fans a greater say in key decisions.
But Theodoridis warned Nandy: "Uefa is concerned about the potential for scope creep within the IFR [independent football regulator].
"While the initial intent of the IFR is to oversee the long-term financial sustainability of clubs and heritage assets, there is always a risk that, once established, the IFR may expand its mandate beyond these areas."
That "could undermine the established structures and processes of the sport, and amount to government interference", he wrote.
He added that it was "imperative to protect and preserve the independence of the FA", and that legislation that "compromises the FA's autonomy as the primary regulator of football in England" would not comply with the Uefa and Fifa statutes.
"It follows that the criteria defining and evaluating the IFR's independence must be meticulously crafted to avoid potential conflicts with the FA's role. This is necessary to prevent sanctions under Uefa and Fifa statutes.
"The IFR's scope must remain focused on the long-term financial sustainability of clubs with a view to ensuring that it does not overstep into areas that might be perceived as external interference in football governance."
Theodoridis also warned Nandy that clauses in the legislation that oblige the regulator to consider the government's foreign and trade policy objectives when deciding on the suitability of future owners "raise specific concerns".
He added that Uefa "respectfully requires further clarification and understanding... in this context to ensure compliance with the Uefa Statutes and to prevent unwanted implications for football governance".
The reintroduced Football Governance Bill will also give the new regulator "backstop powers", which could be used to intervene between the Premier League and the English Football League (EFL) after their failure to agree a funding deal. Talks over a so-called 'New Deal' collapsed in March, with the two organisations unable to agree a funding plan.
In his letter, Theodoridis told Nandy that "the concept of a backstop power introduces significant concerns regarding the balance of power within football governance".
He wrote: "Mandating redistribution which effects the competitive balance in the game and wider European competition would be of concern to us. We also fear that having a third party intervene in redistribution would likely prevent amicable solutions being found.
"As we see it, the 'backstop' power, while intended as a safety net, should be carefully reconsidered to avoid undermining these fundamental principles."
In a statement, the Department for Culture, Media and Sport (DCMS) said: "The Football Governance Bill will establish a new Independent Football Regulator that will put fans back at the heart of the game, and tackle fundamental governance problems to ensure that English football is sustainable for the benefit of the clubs' communities going forward."
Privately, officials are said to believe there is no risk of England being banned by Uefa.
In May, David Newton, the FA's head of football operations, told MPs: "Uefa and Fifa have statutes of their own, which basically prevent state interference in the running of football and football competitions.
"We have worked closely with Uefa and Fifa, and with the DCMS... They have been taken through where we have got to.
"Although we have not had a definitive view as such, it is reasonably clear that a tightness of the bill relating to football governance is not likely to present huge or significant problems, subject to any changes that may occur.
"However, anything wider would increase the risk of Fifa or Uefa intervention. That is obviously a place we do not want to be, because of the sanctions that may flow, in theory, from that."
Niall Couper, chief executive of football campaign group Fair Game, said: "This is nothing short of a scare story.
"With 58% of the top 92 technically insolvent and annual loses of £10m a year in the Championship viewed as 'a success', football is an industry in desperate need of financial reform. The government should not be derailed by such nonsense."
Last month, the Premier League said it "looked forward" to working with the new government, but that "it was critical that the regulation was proportionate and effective".
Uefa declined to comment.