UEFA have opened an investigation into payments made by Barcelona to a former vice president of the refereeing committee in Spain, the body confirmed in a statement Thursday.

Barca paid Jose Maria Enriquez Negreira over €7 million between 2001 and 2018, with Spanish prosecutors alleging they sought favourable treatment from match officials as part of the agreement.

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The Catalan club have denied any wrongdoing, saying they never "bought referees or influence" and that Negreira was tasked with providing "technical reports on refereeing."

LaLiga cannot act against Barca because of the statute of limitations in place in Spain, but UEFA can step in.

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

UEFA added that "further information regarding this matter will be made available in due course."

Charges filed by prosecutors were accepted by a court in Barcelona last week, with a judge agreeing to investigate the case as other Spanish clubs and sporting institutions added their name to the complaint as claimants.

Spain's Higher Sports Council (CSD) confirmed they would join the prosecutors' investigation, and Real Madrid also announced they would join the case "in defence of our legitimate interests" after being the only top-flight club not to sign the initial statement by LaLiga teams condemning Barca's actions.

LaLiga president Javier Tebas has said he does not believe Barca bought off referees but has called on club president Joan Laporta to clear up what he labelled potentially the "biggest reputational crisis" in the league's history.

Laporta has said the constant leaks and stories are the subject of a campaign against Barca and that he will work hard to clear the club's name.