A judge summoned Spanish Economy Minister Luis de Guindos as a witness in an investigation into alleged fraud involving bailout-out bank Bankia, a court said Friday.
The National Court, Spain's top criminal tribunal, summoned the minister to testify on February 18, according to a court ruling.
But since he is a government minister, Guindos has the option of answering questions in writing without going to the court, the ruling added.
The minister said he had "not decided absolutely anything" regarding how he will testify.
"I have no problem with introducing transparency and explaining things to all Spaniards," he added at a news conference following a weekly cabinet meeting.
The investigation centres around Bankia's stock market listing, the forming of the lender from seven troubled savings banks in 2010 and the huge capital shortfall revealed at the bank after the state takeover in May 2012.
The takeover drove Spain to seek up to 100 billion euros ($136 billion) in eurozone rescue funds for its banking sector.
The court opened an investigation in July 2012 into whether former Bankia president Rodrigo Rato and 32 other former board members are guilty of fraud, embezzlement, price manipulation and falsifying accounts following a lawsuit filed by a small political party, UPyD.
Rato, a former head of the International Monetary Fund who resigned from Bankia just before it was nationalised and bailed out for 23.5 billion euros, was questioned as part of the probe on December 20.
He said Spanish authorities held responsibility for events at Bankia including the timing of its ill-fated stock listing.
Bank of Spain governor Luis Maria Linde is scheduled to testify as a witness on February 15, a day after his predecessor Miguel Angel Fernandez Ordonez is set to take the stand, the court said.
Investigating judge Fernando Andreu has so far not brought charges against anyone and could still drop the case.