JERUSALEM - Israel voted in its second election in five months on Tuesday that will decide whether to extend Prime Minister Benjamin Netanyahu's term as the country's longest-serving prime minister despite corruption allegations against him.

The stakes could not be much higher for the 69-year-old right-wing leader who, as in April polls, faces a strong challenge from ex-military chief Benny Gantz and his centrist Blue and White alliance.

Netanyahu voted in Jerusalem alongside his wife Sara and said he expected a close election, calling on Israelis to turn out in large numbers.

" (US) President (Donald) Trump said yesterday that the elections will be tight," Netanyahu said in reference to Monday's comments by the US leader, who has been a strong supporter of the premier, calling the polls"50/50".

"I can guarantee you this morning that they are very tight."

Gantz voted in his hometown of Rosh Haayin near Tel Aviv and called on the country to reject corruption and "extremism".

"We want new hope. We are voting today for change," Gantz said after voting with his wife Revital.

"We will succeed in bringing hope. We will succeed in bringing change, without corruption and without extremism, all together."

Polls opened at 7 am, local time, and were due to close in most areas at 10 pm.

Ex-defense minister Avigdor Lieberman, Netanyahu's former right-hand man turned rival, could play a kingmaker role with his campaign to "make Israel normal again".

About 6.4 million people are eligible to vote.

The first exit surveys will be released just after polls close, while official results are not expected until Wednesday.

Opinion polls have indicated another tight race, showing Netanyahu's Likud and Blue and White winning around 32 seats each in the 120-seat parliament.

Netanyahu and Gantz paid a last-minute visit on Monday night to Jerusalem's Western Wall, the holiest site where Jews are allowed to pray. Netanyahu suffered one of the biggest defeats of his political career following the April vote.

His Likud along with its right-wing and religious allies won a majority, leading Israeli President Reuven Rivlin to task the premier with forming a new government.

But following weeks of discussions, Netanyahu failed, leading him to opt for an unprecedented second election rather than risk having Rivlin choose someone else.

The danger for Netanyahu extends beyond remaining prime minister, a post he has held for a total of more than 13 years.

If he wins, many believe he will seek to have parliament grant him immunity from prosecution while facing the possibility of a corruption indictment in the weeks ahead.

Recognizing the stakes, Netanyahu spent the final days of the campaign seeking to appeal to right-wing nationalists - key to his reelection bid - and to boost turnout among his base.

Those efforts have included a controversial pledge to annex the Jordan Valley, which makes up a third of the occupied West Bank.

Agence France-Presse