Roy Keane wants to see the proposal for six English clubs joining a breakaway European Super League "stopped in its tracks".
Manchester United, Liverpool, Arsenal, Chelsea, Tottenham and Manchester City have signed up to the breakaway plan, according to reports, and will be joined by teams from Italy and Spain.
The former Ireland international, speaking on Sky Sports, blasted the plans.
"I think it comes down to money and greed," he said.
"Obviously we've heard nothing from FIFA yet but it doesn’t sound good. Let’s hope it’s stopped in its tracks.
"We talk about the big clubs. Bayern Munich are one of the biggest clubs in the world – at least they’ve made a stand, which is a good start."
"Let's hope it is stopped in its tracks. It's just pure greed."
Keane's former Manchester United team-mate Gary Neville said: "I'm not against the modernisation of football competitions, we have the Premier League, the Champions League, but I think to bring forward proposals in the midst of Covid and the economic crisis for all clubs is an absolute scandal.
"United and the rest of the Big Six that have signed up to it against the rest of the Premier League should be ashamed of themselves.
"They should deduct six points off all six teams that have signed up to it. Deduct points off them all. To do it during a season? It's a joke."
UK Prime Minister Boris Johnson took to Twitter on Sunday evening to label the proposals "very damaging" and call on clubs to "answer to their fans and the wider footballing community".
He posted: "Plans for a European Super League would be very damaging for football and we support football authorities in taking action.
"They would strike at the heart of the domestic game, and will concern fans across the country.
"The clubs involved must answer to their fans and the wider footballing community before taking any further steps."
😡 | "I'm a #MUFC fan and I'm absolutely disgusted."— Sky Sports Premier League (@SkySportsPL) April 18, 2021
💥 | "They are an absolute joke."@GNev2 gives a brutally honest reaction to reports that England's biggest clubs are expected to be part of plans for a breakaway European Super League. pic.twitter.com/VfJccHgybc
A fuming Neville later added that he was "disgusted" by the developments.
"The reaction to it is that it has been damned, and rightly so. I am a Manchester United fan and have been for 40 years but I am disgusted, absolutely disgusted.
"I am disgusted by Manchester United and Liverpool the most.
"Liverpool, the pretend (with) 'You'll Never Walk Alone’ (they are) the people’s club, the fans’ club.
"Manchester United – 100 years, born out of workers. And they are breaking away into a league without competition, that they can’t be relegated from?
"It is an absolutely disgrace. Honestly, we have to wrestle back power in this country from the clubs at the top of this league, and that includes my club.
"Deduct them all points tomorrow, put them at the bottom of the league and take the money off them. Seriously, you have got to stamp on this.
"It is criminal. It is a criminal act against football fans in this country. Deduct points, deduct money and punish them."
Neville even suggested his old club United, Liverpool and Arsenal should be relegated from the Premier League if they are involved.
"If they announce a letter of intent has been signed, those six clubs, they should be punished heavily. Massive fines, points deductions, take the titles off them. Who cares?
"Give the title to Burnley, let Fulham stay up. Relegate Man Utd, Liverpool and Arsenal. Those three clubs, with their history in this country, are the ones that should suffer the most."
"Manchester United aren't even in the Champions League. Arsenal aren’t even in the Champions League. I watched them earlier today and they are an absolute shambles of a football club"
Neville went on to hit out at the owners of England's biggest clubs.
He added on Sky Sports: "I’ve been calling for 12 months, as part of an another group, for an independent regulator to bring checks and balances in place to stop this happening. It is pure greed.
"They are imposters. The owners of this club (United), the owners of Liverpool, the owners of Chelsea, the owners of Manchester City, they are nothing to do with football in this country.
"Manchester United aren’t even in the Champions League. Arsenal aren’t even in the Champions League. I watched them earlier today and they are an absolute shambles of a football club.
"Tottenham aren’t in the Champions League and they want a God-given right to be in there? They are an absolute joke.
UEFA's executive committee meet on Monday and are expected to agree a controversial revamp of the Champions League.
The so-called 'Swiss model' will see teams compete in one 36-team league - instead of the current system where 32 sides are split into eight pools of four - and guarantee each club 10 matches on a seeded basis.
The new format, which guarantees clubs four more games than in the current group phase, takes the Champions League from 125 to 225 matches and would create a huge headache for domestic schedulers.
However, news of the new format has been overshadowed by the anticipated announcement of the 'Super League'.
UEFA has issued a joint statement with football authorites in England, Spain and Italy and in a solo statement, the English Football Association said it was clear a European Super League would be "damaging to English and European football at all levels" and it would "take any legal and/or regulatory action necessary to protect the broader interests of the English game".
Its statement read: "The FA has been made aware of certain English clubs planning to form a closed European Super League with other European clubs. It is clear that this would be damaging to English and European football at all levels and will attack the principles of open competition and sporting merit which are fundamental to competitive sport.
"For new competitions to be formed involving clubs from different associations, approval would be required from the relevant national associations, confederation and/or FIFA. We would not provide permission to any competition that would be damaging to English football, and will take any legal and/or regulatory action necessary to protect the broader interests of the game.
"We note FIFA confirmed earlier this year that they and the six confederations would not recognise any such competition and, as such, any player or club involved may not be permitted to participate in any official competition which falls within the auspices of FIFA or their respective confederation.
"The FA will continue to work with UEFA, FIFA and the Premier League to seek to ensure that nothing is approved that has the potential to damage English football. We will work with fans, the Premier League, EFL, PFA and LMA, as well as other stakeholders, at home and abroad, to defend the integrity and future prospects of English football in the best interests of the game."