Sánchez has denied any wrongdoing by his wife and has repeatedly dismissed the allegations as part of a smear campaign aimed at undermining his government.

Gómez is being investigated for alleged influence peddling and corruption following a complaint filed by an anti-graft NGO with links to the far-right called “Manos Limpias” — Spanish for “Clean Hands”.

Judge Juan Carlos Peinado, who is heading the inquiry, on Monday called on the Socialist premier to testify as a “witness” as part of the investigation into the influence peddling allegations.

The judge said he would question Sánchez at his official residence on July 30 at 11 am (0900 GMT).

“I am willing, because it cannot be otherwise, to cooperate with the judicial administration, always in strict compliance with the framework established by the Spanish constitution,” Sánchez said in a court filing sent to the judge, a copy of which was obtained by AFP.

But “because of my position as prime minister, my statement will have to be made in writing,” as allowed under Spanish law, he added.

“As prime minister, it is my duty to respect the law and preserve the proper functioning of the institution I represent,” Sánchez said.

Gómez, who has worked in fundraising for years, notably for foundations and NGOs, is alleged to have used her husband’s position as leverage within her professional circles, notably with businessman Juan Carlos Barrabés who was seeking public funding.

Barrabés – who teaches part of a master’s course at Madrid’s Complutense University that is run by Gómez – acknowledged meeting her five or six times at Moncloa, the premier’s official residence, while testifying.

Sánchez, in power since 2018, was also present at two of those meetings, he said.

Barrabés — who got two letters of recommendation from Gómez before pitching for a public tender worth several million euros — said they only talked about matters of innovation, judicial sources said.

Gómez on Friday invoked her right to remain silent under questioning by a judge.

When the probe was opened in April, Sánchez shocked Spain by saying he was considering resigning over what he denounced as a campaign of political harassment by the right.

He took five days to reflect but ultimately decided to stay on.