In a televised address, he said he would “continue to lead Israel responsibly and faithfully”, describing the allegations as “baseless”.
His long-running political career had been solely “for the good of the nation”, he said.
In addition, he accused police of conducting a witch hunt against him, and said he would run for re-election.
Mr Netahyahu, who has been questioned several times since the start of 2017, is a suspect in two separate cases.
In one of them, he is alleged to have received $100,000 in gifts from Hollywood mogul Arnon Milchan and other wealthy supporters.
In the other case, he is accused of offering preferential treatment to a newspaper publisher in exchange for favourable coverage.
More from World
South African President Jacob Zuma refuses to resign despite being sacked by party
Palestinian teenager Ahed Tamimi on trial after viral slapping video
US drone destroys Russian-made tank in Syria
Donald Trump ‘taking an axe’ to US governance, John Oliver says
Duterte says female rebels ‘should be shot in genitals’
Who is controversial Saudi Crown Prince Mohammed bin Salman?
He denies any wrongdoing.
A decision on whether to press charges will be taken by Israel’s attorney general.