Barcelona are facing the threat of being banned from the Champions League, with UEFA to investigate the payments made by the club to a former vice-president of Spain's referees' committee.

Court documents showed that the Catalan outfit paid €7.3m (£6.4m) between 2001 and 2018 to two companies which were owned by Jose Maria Enriquez Negreira.

Champions League regulations, which have been in place since 2007, allow UEFA to suspend teams from the competition for a season if they are found to have been involved in match fixing.

UEFA have now requested an investigation, the outcome of which could see Barcelona issued a suspension from the European Cup for the 2023-24 campaign.

Barcelona went out in the group stage of this season's Champions League, before being knocked out of the Europa League in the playoff round by Manchester United, but they are well on course to qualify for next season's competition, sitting comfortably at the top of the La Liga table.

"In accordance with Article 31(4) of the UEFA Disciplinary Regulations, UEFA Ethics and Disciplinary Inspectors have today been appointed to conduct an investigation regarding a potential violation of UEFA's legal framework by FC Barcelona in connection with the so-called 'Caso Negreira'," read a statement from UEFA.

"Further information regarding this matter will be made available in due course."

Barcelona have insisted that they simply paid for technical reports on referees, but it is alleged that individual games were potentially influenced by Negreira, who is the former vice-president of Spanish football's refereeing committee.

The club's former presidents Josep Maria Bartomeu and Sandro Rosell have also been hit with corruption charges as part of the investigation.

Prosecutors in Spain are accusing the Catalan outfit of fraudulent management, breach of trust and falsification of business documents, with the charges arising following an inspection by tax authorities.

"Let it be clear Barca have never bought referees and Barca have never had the intention of buying referees, absolutely never," current Barcelona president Joan Laporta said earlier this month.

"It's not chance that this comes out now, when Barca are doing well."

Barcelona moved 12 points clear at the top of the La Liga table courtesy of a 2-1 victory over Real Madrid in El Clasico last weekend, and they will next be in action away to bottom-of-the-division Elche on April 1.