Spain's secretary of sport Miguel Cardenal has described as "very serious" reports that Spanish FA [RFEF] chief Angel Maria Villar broke his own organisation's rules to help out struggling third-tier club Recreativo de Huelva.
The Spanish government is investigating whether fraud took place amid claims that the RFEF disregarded its own rules to give Recreativo a license to compete despite being technically bankrupt, according to an El Pais report.
Reports also say the Andalucian club received a direct €200,000 loan, which was used to make a payment to a former coach, even though it has an unpaid tax bill of €11 million and has been embargoed by the authorities.
In recent years other Spanish clubs in similar difficulties including Elche and Huesca have not received such favourable treatment and been forcibly relegated when it became clear they had been living beyond their means.
Asked about the situation by El Pais, Cardenal said his department had asked the federation to give their version of events in what is "an extraordinary serious case."
"The behaviour described in news reports published is very serious," he said. "Last week we asked for written explanations from the federation and we have given them a short period of time to supply the documents relevant to the alleged acts.
"I would like to restate that this is an extraordinary serious case. You cannot treat different clubs different ways. The rules must be followed, and the federation has an obligation to conserve its assets, and not make loans which might not be repaid."
Recreativo executive Pablo Comas has already resigned after the payments came to light at the club.
Villar has been Spanish FA president since 1988, but has clashed repeatedly through recent years with both Cardenal and La Liga president Javier Tebas. The former Athletic Bilbao midfielder, 66, faces a challenge in upcoming election from the federation's secretary general Jorge Perez.
Should the Spanish government find that the support provided to Huelva was illegal, reports have claimed that Villar would not be allowed to run for re-election.
Villar is also a FIFA vice president, and has been very close through recent years to Sepp Blatter and Michel Platini. Late last year he was appointed as acting chairman of the Organising Committee for World Cup 2018. He is not, however, close to any of the candidates running to become new FIFA president at the elections on Feb. 26.