Allegations that the payments are dished out -- usually to teams which no longer have anything to play for that are facing a well-placed squad still in the race for a title -- have swirled around Spanish football for years.

But with the approach of the end of an especially tight La Liga championship season this weekend, Spain's sports media have in recent days thrown the spotlight on the practice.

"We know this exists but as long as no complaint is filed, we can't do anything," a spokesman for the Spanish football federation told AFP.

"Several inquiries have been opened in recent years following complaints but we have never managed to prove that these payments were made so no penalty has ever been handed out," he added.

Sports daily Marca has reported that Real Mallorca have been promised two million euros (2.7 million US dollars) if they defeat or draw against Real Madrid on Sunday.

Real Madrid, which is tied with arch rivals Barcelona on 73 points with one round left, need to beat Real Mallorca to win La Liga for a record 30th time.

The newspaper said each Real Zaragoza player received 50,000 euros following their side's 2-2 draw against Real Madrid on Saturday.

The players would have received double that amount had they defeated Real Madrid, it added.

"Everyone talks about bonuses but nobody sees them. Our dream is only to win the title, for us and our fans," Real Madrid goalkeeper Iker Casillas told a news conference Tuesday when asked about the reports.

"The most important bonus is winning La Liga," he added.