Main Netanyahu challenger to launch election bid

A former Israeli military chief regarded as the only serious challenger to Prime Minister Benjamin Netanyahu was to formally launch his election campaign on Tuesday.

Benny Gantz was to deliver a speech in Tel Aviv to "discuss all the issues at hand" and respond to claims made against him by political opponents, a source close to the retired general said.

His party, Israel Resilience, is set to be the second largest in parliament in the April 9 vote, according to a series of polls since its launch in December.

The widely respected former military chief of staff, seen as a political centrist, has kept his cards close to his chest and made few public comments.

In a rare remark, he committed to amend a contentious law defining Israel as the nation state of the Jewish people in order to accommodate its Druze minority, leading to Netanyahu calling him a "leftist".

Apart from messages on social media promising "something different" for Israel and a song pledging "no more right or left", Gantz has played up his military credentials.

Gantz has boasted in videos of the number of Palestinian militants killed and targets destroyed under his command in the 2014 war with Gaza's Islamist Hamas rulers.

In another video, Gantz stresses the need to strive to make Arab-Israeli peace.

Opinion polls show Netanyahu winning the April polls but the long-serving premier faces potential corruption charges that could shake up the campaign.