Polls closed in the race to lead Israel's ruling Likud party Thursday, with embattled Prime Minister Benjamin Netanyahu and rival Gideon Saar set to find out who would take the party into March elections.

Forty-nine percent of Likud's roughly 116,000 eligible members voted throughout the day, according to party figures.

The result is expected early Friday.

A defeat for Netanyahu, Israel's longest-serving premier, would be a shock, but even a relatively close victory could weaken his influence over the right-wing party he has dominated for 20 years.

After a decade in power, the 70-year-old has recently been damaged by a series of corruption indictments.

Israeli Prime Minister Benjamin Netanyahu, who faces a party leadership challenge on Thursday, addressed Likud party supporters during a meeting in the Israeli city of Petah Tikva near Tel Aviv on December 18
Israeli Prime Minister Benjamin Netanyahu, who faces a party leadership challenge on Thursday, addressed Likud party supporters during a meeting in the Israeli city of Petah Tikva near Tel Aviv on December 18 AFP / Jack GUEZ

The winner will lead Likud into a third general election within 12 months in March, after previous elections last April and September had seen it deadlocked with the centrist Blue and White party and neither one able to form a government.

With storms lashing the country, early indications suggested turnout would be low -- prompting Netanyahu to issue a plea to voters.

"Everything is within reach, but only if you get out to vote," he said on Twitter.

"The low percentage of turnout hurts us."

His Facebook page showed a live video of him working the phones calling voters.

Israeli Likud party member and former interior minister Gideon Saar is up against Netanyahu for leadership of their right-wing party
Israeli Likud party member and former interior minister Gideon Saar is up against Netanyahu for leadership of their right-wing party AFP / JACK GUEZ

Saar, 53, a former interior and education minister, is seen as slightly to the right of Netanyahu and has called for an even more hawkish policy towards the Palestinians.

Saar called it a "fateful day" for the party and the country, speaking as he went to vote near Tel Aviv.

"We can win today and embark on a new path, which will enable us to form a strong and stable government," he said.

Netanyahu cast his vote in a booth set up in his residence, while Saar visited a polling station near the commercial capital Tel Aviv.

Israeli Likud party member and former interior minister Gideon Saar is up against Netanyahu for leadership of their right-wing party
Israeli Likud party member and former interior minister Gideon Saar is up against Netanyahu for leadership of their right-wing party AFP / JACK GUEZ

On Wednesday evening, Netanyahu was rushed off stage at a campaign event in the southern city of Ashkelon, near Gaza, after alarms indicating incoming fire from the Palestinian enclave.

At a polling station in Jerusalem's Kiryat Moshe neighbourhood, Rami David said he had voted for Saar because "he would give Likud a new image".

Nathan Moati, 26, said he backed Netanyahu and didn't think supporters were concerned by the indictment he faces.

"The most important thing is to vote overwhelmingly," he said, adding that he hoped for an 80-20 percent majority for Netanyahu.

Stephan Miller, a pollster who has worked on multiple Israeli campaigns, said whatever the result "Netanyahu can only lose" because "it will be the first time in 10 years that a group of voters on the right explicitly express their desire to get rid of Netanyahu".

The election comes after a troubled year for Israeli politics and the premier.

General elections in April and September saw Netanyahu deadlocked with centrist challenger Benny Gantz, neither of them able to command a majority in Israel's parliament.

Last month, Netanyahu was indicted for fraud, bribery and breach of trust in three corruption cases, allegations he strongly denies.

Netanyahu has sought to paint himself as an irreplaceable leader fighting a "witch hunt" by the police, the legal establishment and the media.

The primaries were called shortly after the charges were issued.

A series of polls in recent weeks have indicated a Saar-led Likud might win fewer seats in a third election than under Netanyahu, but the overall right-wing bloc might be larger -- potentially yielding a viable governing coalition.

Saar has not attacked Netanyahu personally and even hinted that he would support him to become Israel's president, a largely ceremonial role.

Netanyahu's downfall has been predicted multiple times since he became premier for a second time in 2009, but he has defied expectations and appears determined to fight on.

Under Israeli law, a prime minister is only forced to step down once convicted with all appeals exhausted.