Netanyahu denounced what he called the "false" and "politically motivated" allegations, hours after being charged by the attorney general with bribery, fraud and breach of trust.
"What is going on here is an attempt to stage a coup against the prime minister," Netanyahu said.
"The object of the investigations was to oust the right wing from government."
In a 15-minute speech, Netanyahu railed against his political rivals and state institutions, accusing the police and judiciary of bias.
The veteran politician argued that it was time for an "investigation of the investigators".
He vowed to continue as prime minister despite potential court dates and intense political pressure.
"I will continue to lead this country, according to the letter of the law," he said. "I will not allow lies to win."
Political rival Benny Gantz, who had been trying to form a coalition government, said it was a "very sad" day for Israel to indict a leader, but called on Netanyahu to "step down from his position and focus on the charges against him".
"There is no coup in Israel, but rather those that have barricaded themselves in power," he said.
The 70-year-old premier, nicknamed "Mr Security" and "King Bibi", has been in power since 2009 and dominates Israel's political scene.
The indictment comes with crunch talks due on forming a government, after two inconclusive general elections left the country's political system deadlocked.
Netanyahu is not legally required to resign unless he is convicted and any subsequent appeals process is exhausted, but political pressure is likely to be intense.
He may now ask the parliament, or Knesset, to grant him immunity from prosecution.
Agencies contributed to this report.
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