Public radio said Sara Netanyahu arrived at the headquarters of the National Fraud Squad, near Tel Aviv, late in the morning.
There was no immediate confirmation from police, who have issued statements on previous interrogations of the Netanyahus on a raft of different graft allegations only after the day's questioning was over.
On Sunday, police recommended charging the premier and his wife for bribery and other offences.
It was the third such recommendation against them in recent months. Netanyahu denied the accusations, but the cases against him have led to speculation that they could eventually force the long-serving prime minister to step down.
Sara Netanyahu went on trial in October for allegedly using state funds to fraudulently pay for hundreds of meals.
It said that if the suspicions are verified, they would be added to evidence in her existing trial.
The case put forward by police on Sunday is a separate matter, which centres on regulatory benefits allegedly granted to telecommunications firm Bezeq in exchange for positive coverage of Netanyahu from a related media company.
Police in February recommended indicting Netanyahu in two other corruption investigations.
The attorney general must decide whether to file charges.
In the findings announced Sunday following a long-running investigation, police said there was evidence to indict Netanyahu with bribery, fraud, breach of trust and unlawful acceptance.
They recommended Sara Netanyahu go on trial for bribery, fraud, breach of trust and obstruction of justice.
The premier has repeatedly called the allegations against him a plot by his political enemies to force him from office.
The recommendations in February involved separate cases of alleged bribery.
In one, allegations against Netanyahu include seeking a secret deal with the publisher of Israel's top-selling newspaper Yediot Aharonot to ensure positive coverage in return for pushing forward a law that would have limited the circulation of a rival.
The other case involves suspicions the premier and his family received luxury gifts from wealthy individuals in exchange for financial or personal favours.
The alleged gifts -- including cigars, jewellery and champagne -- had an estimated value of around one million shekels (USD 270,000), police say.
Netanyahu has been prime minister for a total of more than 12 years, from 1996 to 1999 and again since 2009.
Polls suggest he would still win if elections were to be held now despite the accusations.
He could next year surpass the record set by Israel's founding father David Ben-Gurion, who spent more than 13 years in office.
He is not legally required to step down if indicted -- only if he is convicted with all avenues for appeal exhausted.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)