TEL AVIV • Israel's Prime Minister Benjamin Netanyahu has slammed what he called a "left- wing and media campaign" aimed at overthrowing him as he faces ongoing investigations.

"The media has mobilised in an obsessive campaign against my family and me, but you the voters are the ones really targeted," he said at a rally of his right-wing Likud Party in Tel Aviv on Wedneday.

The rally came after officials last week said Mr Netanyahu's former chief of staff, who has been investigated in graft cases involving the premier, had agreed to turn state witness.

According to reports, Mr Ari Harow has already been supplying investigators with information regarding two of the investigations.

One is based on suspicions that Mr Netanyahu unlawfully received gifts from wealthy supporters, including Australian billionaire James Packer and Hollywood producer Arnon Milchan.

Also being probed are allegations that he sought a secret deal with the publisher of top-selling daily Yediot Aharonot.

The deal, not believed to have been finalised, would reportedly have seen Mr Netanyahu receive positive coverage in return for helping scale down the operations of Israel Hayom, Yediot's main competitor.

Mr Netanyahu has been questioned about both cases.

For months, Israeli television channels and newspapers have been publishing revelations regarding the probes into Mr Netanyahu's alleged wrongdoing, and predicting his downfall.

"Their purpose is a governmental coup," he told supporters, estimated by organisers to number 3,000. "Their goal is to apply unrelenting pressure on law enforcement agents so that they'll serve an indictment at all costs, without taking into account the truth or justice."

The premier has rejected allegations of misconduct , saying repeatedly that he is the target of a campaign by political opponents.

"The people are with us," Mr Netanyahu said at the rally, accompanied by his wife, Sara, who has also been grilled on suspicion that she diverted public money for private housekeeping expenses.

If Mr Netanyahu is forced to resign, new elections could be declared, with polls showing Mr Yair Lapid of the opposition Yesh Atid party and Finance Minister Moshe Kahlon of the Kulanu party as top contenders to replace him, along with new Labour Party leader Avi Gabbay.

AGENCE FRANCE-PRESSE, BLOOMBERG