Barcelona will not apologise for their role in creating the failed European Super League and will appeal against any punishment from UEFA, president Joan Laporta said on Friday.

Barcelona, Real Madrid and Juventus are the last ones standing of the 12 clubs that signed up to the breakaway project in April, only for it to unravel when all six English sides plus Inter Milan, AC Milan and Atletico Madrid withdrew.

UEFA opened disciplinary proceedings against Barca, Real and Juve on Tuesday, prompting the three clubs to issue joint statements saying they would not bow down to pressure from the governing body.

"I've told (UEFA president Aleksander) Ceferin that we aren't going to say sorry. And we don't plan on paying any sanction," Laporta told a news conference on Friday.

"If we are sanctioned we'll go to the Court of Arbitration for Sport (CAS)."