Cristiano Ronaldo could face a minimum of six years in jail, the secretary general of the union at Spaininfo-icon's tax authority (GESTHA) has claimed.

Jose Maria Mollinedo of GESTHA was speaking to Spanish radioinfo-icon station RAC1 when he revealed the sheer scale of the trouble Ronaldo could find himself in.

Newspaper El Mundo reported this week that the Real Madrid star has directed at least EU150million in income through tax havens, including the British Virgin Islands, since 2009.

Ronaldo's agency, Gestifute, issued a strong denial and published documents that they believe prove Ronaldo is innocent.

But Mollinedo, one of the tax workers' union's most senior figures, suggested Ronaldo may well be facing a prison sentence.

"The information about Cristiano Ronaldo makes it look like he could have defrauded more than EU150million," he said.

"We'd be looking at a major fiscal crime. This would fit a minimum prison sentence for each tax year of the fraud. If the open inspection is for three years, [then it would be] a minimum of six years in prison.

"If, before two months have passed from the opening of the investigation, they legally recognise the facts and pay back the defrauded amount, the punishment can be reduced."

Carlos Cruzado, GESTHA's president, told Cadena Ser that he expects Ronaldo to go to trial over the charges.