Football super-agent Jorge Mendes denied Tuesday he helped create shell companies for his clients during questioning by a Spanish court investigating alleged tax evasion by Monaco striker Radamel Falcao.

He told the closed door hearing in Pozuelo de Alarcon, an upmarket suburb of Madrid where many football stars live, that he "never" advised players in tax matters", his company Gestifute said in a statement.

Mendes added that "as an agent he is limited to representing athletes in their negotiations with clubs to determine salary conditions in their contracts," the statement added.

As Spanish authorities tighten the net around footballers such as Real Madrid superstar Cristiano Ronaldo, another Mendes client suspected of fiscal fraud, their advisers and agents are coming under scrutiny too.

Monaco's Falcao is suspected of failing to correctly declare 5.6 million euros ($6.3 million) of income earned from image rights between 2012 and 2013 while he was at Atletico Madrid.

The Colombian is accused of using a web of shell companies in the British Virgin Islands, Ireland, Colombia and Panama to avoid taxes on the image rights income.

The court notified Mendes during the hearing that he is charged with "suspicion of collaboration in the process" that led Falcao to "commit a tax offence", a judicial source told AFP.

Wearing a dark suit and black tie, the 51-year-old made no comments as he entered and left the court.

- Falcao's wife testifies -

Mendes saw the judge just after Falcao's Argentine wife Lorelei Dahiana Taron, who is merely appearing as a witness, a judicial source told AFP.

His company Gestifute had already denied any wrongdoing.

"Neither Jorge Mendes nor the company he manages, Gestifute, participate in or offer any service linked, directly or indirectly, to financial, fiscal or legal advice to their clients," it said earlier this month.

But it is emerging that some of the clients of the man who has been elected "best agent of the year" several times at the Globe Soccer Awards are being targeted by tax fraud investigations.

Ronaldo himself, the world's highest paid athlete according to Forbes, is due to be questioned by a Spanish judge on July 31 after allegedly evading 14.7 million euros in taxes.

Fabio Coentrao, the Portugal international who also plays for Real Madrid, is suspected of having hidden close to 1.3 million euros in revenues.

And Manchester United manager Jose Mourinho, another Mendes client, has been accused of failing to pay millions of euros in taxes during his time in charge of Real Madrid.

In this case though, Mendes' company Gestifute said Mourinho had resolved the situation with tax authorities.

Football Leaks

Mendes, a former nightclub manager, found himself in the eye of the storm last year in the "Football Leaks" media investigation into alleged soccer corruption.

Based on millions of documents, the investigation claims he offered his clients ways to avoid paying taxes on some of the money they earned.

According to the EIC media consortium he allegedly helped them evade a total of 185 million euros in advertising revenues "via a network of shell companies and offshore accounts in Ireland, in the British Virgin Islands, Panama and Switzerland."

To do so Mendes allegedly used Irish firm Polaris, an accusation he denied in court on Tuesday.

The agent told the hearing that Polaris "is not managed by him and is dedicated exclusively to finding advertisers for clients," the Gestifute statement said.

Born to an oil industry worker in Lisbon, Mendes left the Portuguese capital aged 19 to enter the business world in the northern provincial town of Viana do Castelo.

A video rental business which he opened became a successful venture and soon he would meet Portugal keeper Nuno Espirito Santo in a disco he was also running.

A former semi-professional footballer himself, Mendes set about cultivating close links to players, creating his own network and starting to look afer their interests.