The 123,000 registered members of Israeli Prime Minister Benjamin Netanyahu’s ruling rightwing Likud party began casting votes in a leadership primary on Sunday ahead of a general election on January 22.
Polling stations opened at 9:00 am (0700 GMT) and were to close 13 hours later at 10:00 pm (2000 GMT) with the results expected out by midnight (2200 GMT).
Sunday’s primary will decide who makes it onto the party list which will be put to voters in the January election.
Analysts are keen to see if the party tilts further to the right in response to public disaffection over a truce deal which on Wednesday ended Israel’s eight-day Operation Pillar of Defence against Gaza militants, halting plans for a major ground operation.
The main issue likely to be revealed by the ballot is the strength of the far-right Jewish settler lobby within the party.
Last week, the settler lobby published a front-page advert in the English-language Jerusalem Post ranking Likud candidates on the basis of their opposition to a Palestinian state and how many settlements they had helped build in the occupied West Bank.
According to army radio, Netanyahu has been putting pressure on his supporters to work to block any candidates seen as too extreme so that he will be able to present a “moderate” list which will not alienate centrist voters.
The vote comes just four days after Israel agreed to end its week-long campaign in Gaza, accepting an Egyptian-brokered ceasefire deal with Hamas without sending troops in for a widely-expected ground operation.
According to a poll published on Friday by the Maariv newspaper, 49 percent of respondents thought Israel should have continued the operation in Gaza, while just under a third — 31 percent — agreed with the decision to accept a truce.
Netanyahu has insisted that Israel’s relentless bombardment of Gaza met all its objectives.
But it appeared the message was not getting through.
The Maariv survey showing that if an election were to be held now, Likud’s joint list with the ultra-nationalist Yisrael Beitenu headed by Foreign Minister Avigdor Lieberman, would win only 37 seats compared with the 43 projected in a poll at the end of October.
They hold 42 seats in the outgoing coalition government.