Two weeks ago, the police submitted recommendations that the prime minister be indicted in connection with two other cases, also relating to bribes, fraud and breach of trust.
Mr Netanyahu was questioned at his official residence just hours before he was due to fly to the United States.
Army Radio and other media say police entered Netanyahu's residence on Friday. Nir Hefetz was Mr Netanyahu's head of communications and David Sharan served as his chief of staff.
Sara Netanyahu will be questioned from 8:30 am at Israel Police's Lahav 433 anti-corruption unit in Lod.
The Israeli prime minister, in an apparently unrelated case, is also subjected to accusations that he and his spouse misappropriated public funds to pay for private expenses, ranging from laundry to ice cream.
Now at the center of three corruption probes, Netanyahu denies any wrong doing calling the allegation against him a 'witch-hunt'.
This, said the TV channel, turns Sara Netanyahu into a suspect in the case.
Meanwhile, Bezeq Telecom's controlling shareholder Shual Elovitch along with a former Netanyahu spokesperson are in police custody.
The first case involves Israeli Hollywood producer Arnon Milchan, who was allegedly asked to purchase luxury items for Netanyahu and his wife.
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Justice Minister Ayelet Shaked, a member of the ultranationalist party Jewish Home, said that according to the law, Netanyahu can stay in the job through the end of his trial.
Some drivers touted their horns in support as they drove by.
The rightwing prime minister has been Israel's dominant political figure for a generation, in power since 2009 and for 12 years in total since 1996.
In one, known as Case 1000, he is suspected of bribery over gifts, which police say were worth almost $300,000, that he received from wealthy businessmen. The case involves allegations of government officials trading regulatory benefits for Bezeq, a top telecommunication firm, in return for positive media coverage of Netanyahu and his associates.
Israel's attorney general, Avichai Mandelblit, must decide whether to press charges in either case, a decision that could take months.
So far, partners in Netanyahu's governing coalition have stood by him, saying they were awaiting the attorney-general's next moves.
In Case 4000, investigators say the ministry illegally advanced Bezeq's interests in exchange for favorable news coverage for the Israeli leader. A third think he should remain in office.
Recent polls show that about half of Israelis believe the police over Netanyahu and think he should step down.