Barcelona president Joan Laporta insisted Monday his club never tried to cheat amid investigations into payments made to a former refereeing chief.

In a two-hour news conference, he said there was a smear campaign against Barcelona and the head of La Liga for backing the case against the Catalan club, who are top of the league.

"Obviously referees were not bought and there was no attempt to influence their decisions," he told reporters gathered at the club's Camp Nou stadium.

"Barcelona has never done anything with the aim or intention of adulterating the competition in order to gain a sporting advantage."

Last month Spanish prosecutors charged the Catalan club with corruption after payments of more than 7.3 million euros ($7.8 million) to a company owned by a former refereeing chief were uncovered earlier this year.

Barcelona say they paid Jose Maria Enriquez Negreira, the former referee and ex-vice president of the refereeing committee of the Spanish football federation (CTA) between 1994 and 2018, for reports and advice related to refereeing.

Barcelona ceased its payments in 2018 due to Negreira's departure from the CTA, according to Spanish prosecutors.

Laporta said the payments were for "sports advisory services" such as advice on recruiting "which are common in professional sport".

"There was no crime of corruption," he added in his first press conference since Barcelona was charged.

"Some services were provided. They were documented. There were invoices, payments registered in the accounting books."

Laporta said Spain's tax office has not been able to demonstrate that the payments "could have influenced the referees or the result of any match."

"They have not been able to prove it because it was not possible," he added.

"We like to win by playing well. We don't like to win because of refereeing."

As well as the club and Enriquez Negreira, two of the club's former presidents, Josep Maria Bartomeu and Sandro Rosell, are facing the same charge of corruption.

Verbal incontinence

La Liga president Javier Tebas has said Spanish football is enduring its "worst" ever moment because of the refereeing corruption case. 

"The reputation of our football is at stake. I am ashamed. We have no explanation from Barcelona," he added last month.

Tebas has repeatedly urged Barcelona to offer more explanations.

Laporta, however, said they accusations of wrongdoing were part of "an orchestrated campaign to destroy the reputation of FC Barcelona."

"I would like to single out, in particular, Tebas, who has acted irresponsibly and unprofessionally. With his constant statements, he has fuelled the controversy," he added.

"I would ask him to curb his verbal incontinence because it does no favours to the institution he represents."

UEFA have opened an investigation into Barcelona for a potential violation of the European soccer governing body's legal framework regarding payments made by the club to a company owned by a top refereeing official.

Laporta said he was confident UEFA would not sanction the Catalan side.

"I am convinced that it will not come to that, that would be unprecedented for a club with FC Barcelona's level," he said.