"We are surprised," Messi said on his Facebook account, "because we have never committed any infringement.

"We have always fulfilled all our tax obligations, following the advice of our tax consultants who will take care of clarifying this situation."

Messi (pictured) and his father are accused of allegedly defrauding more than €4 million in income tax returns for the years 2006, 2007, 2008 and 2009.

They allegedly avoided taxes by pretending to cede their image rights to companies based in tax havens such as Belize and Uruguay. They are also accused of deliberately setting up image-rights deals in Britain and Switzerland. Messi and his father acted with "total opaqueness" towards the Spanish authorities, the filing said.

A judge at the court must accept the prosecutor's complaint before charges can be brought.

"It is all a mistake, you have to speak about this to the tax experts and lawyers who need to clear it up," the father told Spanish sports daily . "I don't understand what is going on. I don't manage these matters."

The complaint was filed a day after Messi played in Argentina's 1-1 draw against Ecuador in a World Cup qualifier in Quito. Argentina coach Alejandro Sabella said Messi was expected to be included in the line-up for a friendly against Guatemala tomorrow.

Messi, who will be 26 this month, is one of the world's highest-paid athletes with a salary of just over US$20 million a season, according to magazine.

He pulls in around US$21 million in endorsements from sponsors including Adidas, PepsiCo and P&G and is 10th on ' latest list of top-earning athletes.

Assoicated Press, Reuters, Agence France-Presse