© Getty Images Enlarge Neymar can potentially make €7 million more per year than Lionel Messi

Barcelona may be forced to spend millions of euros making Lionel Messi their highest-paid player when the full details of Neymar's transfer and contract come to light, according to reports in Spain.

Barca president Sandro Rosell maintains the club paid 'just' €57.1 million to sign Neymar from Santos last summer. However he has not specifically denied claims in El Mundo that Neymar and his father/agent received more than €60 million in various commission and signing-on fees between them.

The deal is currently under investigation by a Spanish judge and AS reports that, should details emerge that Neymar is earning significantly more than meets the eye, a number of Barcelona players will look for improvements to their contracts, with four-time World Player of the Year Messi likely to be at the front of the queue.

Neymar's basic salary is thought to be €6 million a year, with bonuses for winning trophies and meeting certain individual targets. If the extra €60 million he reportedly earns is spread over the five years of his contract, he would take home more than €18 million a year - well above Messi's reported €11 million. Cristiano Ronaldo is now believed to earn €20 million since signing his new Real Madrid contract last September.

Messi - set to make his 400th Barca appearance in Wednesday's Copa del Rey quarter-final first leg at Levante - last extended his contract in February 2013, committing to Camp Nou until June 2018, in what was his sixth renewal in eight years.

He regularly maintains he does not worry about money, but his reaction was prickly when Barca vice-president Javier Faus suggested in December that there was "no reason" to talk about a new deal.

That well-publicised argument, and accompanying reports that Paris Saint-Germain and Manchester City were looking to take advantage of the situation, has also strengthened the hand of Messi's father and agent, Jorge, in contract talks.

Members of the Barcelona board, including Rosell, have regularly stated publicly since then that Messi is the best player in the world and deserves to be the best paid, with Faus echoing that view just this week as the Neymar controversy intensified.

Other players including Cesc Fabregas, Sergio Busquets, Alexis Sanchez and Gerard Pique - all due to begin initial new contract talks soon - may also look at Neymar's figures as a benchmark when deciding how much they are worth.

AS suggests that should Barca, €330 million in debt and planning a €600 million upgrade of Camp Nou, not meet these new expectations, Europe's big spenders will be ready to pounce.

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