Former Israeli defence chief Gadi Eisenkot is emerging as the main rival to incumbent Prime Minister Benjamin Netanyahu, months ahead of the nation’s parliamentary elections.

Eisenkot’s new centrist party, Yashar! (Hebrew for “Straight!”), has rapidly been gaining popularity in opinion polls. It is currently second behind Netanyahu’s right-wing Likud.

Israelis must elect a new parliament by October 27 at the latest, although the vote was most likely to be held on October 20. Opinion polls suggest it could prove difficult for both Netanyahu’s camp and the opposition to secure a majority. Israeli coalitions are usually composed of several parties.

Netanyahu, 76, is the longest-serving premier the country has ever had. Polls remain challenging, with a recent survey showing that a majority of Israelis want him to leave office.

Public opinion is critical of the war that Israel and the US launched on Iran in late February, whose ceasefire talks Israel was left out of, leading to a deal between Iranians and Americans viewed as unfavourable to Israel.

A recent poll by the Hebrew University of Jerusalem found that over 92 per cent of Israelis believe Iran had won the war, and support for Netanyahu’s premiership plummeted from 40.5 per cent in early March to 29.4 per cent in June.