Israelis voted on Tuesday in a high-stakes election that will decide whether to extend Prime Minister Benjamin Netanyahu's long right-wing tenure despite corruption allegations or to replace him with an ex-military chief new to politics.

The vote is expected to be close and likely lead to frantic negotiations to form a coalition once results are in, with opinion polls having shown Netanyahu best placed to do so.

Polls were to close at 1900 GMT in most areas, with final results not expected until early on Wednesday.

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Ex-military chief Benny Gantz has mounted a strong challenge to the veteran prime minister by brandishing his security credentials while pledging to undo damage he says Netanyahu has inflicted on the country with divisive politics.

He voted in his hometown of Rosh Haayin and called for a "new path".

"I'm happy to stand for the good of the citizens on a new path," he said after casting his ballot.

"We shall respect democracy and call for a respectful and quiet day from all sides."

Netanyahu was to vote later in the day.

The election was in many ways a referendum on the 69-year-old who has built a reputation as guarantor of the country's security and economic growth, but whose populism and alleged corruption have left many ready for change.

He has engaged in populist rhetoric that critics say amounts to the demonisation of Arab Israelis and others.

True to form, Netanyahu issued a deeply controversial pledge only three days before the election, saying he planned to annex settlements in the occupied West Bank should he win.

Read: Palestine, Turkey denounce Netanyahu's campaign pledge to change West Bank status

Extending Israeli sovereignty on a large-scale in the West Bank could be the death knell to already fading hopes for a two-state solution with the Palestinians.

It is a move long-sought by Israel's far-right.

Ronit Kampf, a 45-year-old university professor, was among the first to cast ballots at a Jerusalem polling station and said she was concerned by the corruption allegations.

"Bibi has been in power too long," she said, using Netanyahu's nickname.

"There is going to be a big change. What kind of change, I don't know exactly, but there will be a change."

'Need for change'

Netanyahu has sought to portray himself as Israel's essential statesman in the run up to the vote and highlighted his bond with US President Donald Trump.

He has spoken of Trump's recognition of Jerusalem as Israel's capital and of Israel's claim of sovereignty over the Golan Heights, while saying the US leader is aware of his annexation plans.

Read: Do Trump and Netanyahu have a mutually beneficial relationship?

"Who else can do this? Who can do this? Come on. Honestly," Netanyahu said in an interview on Sunday with local news site Arutz Sheva.

"Who can stand in front of the world? Who can stand in front of the American Congress? Who can move public opinion in that direction?"

At the same time, he has used Trump-like tactics, calling the corruption investigations a "witch hunt" and denouncing journalists covering them.

On Monday night, he paid a visit to Jerusalem's Western Wall for a last-minute prayer.

Gantz, a 59-year-old former paratrooper who has formed a centrist alliance to challenge Netanyahu, has invoked the corruption allegations against the premier to make his case that it is time for him to go.

He has called Netanyahu's annexation pledge an "irresponsible" bid for right-wing votes.

Gantz says he favours a "globally backed peace agreement" that sees Israel hold on to the large settlement blocs in the West Bank and maintain security control over the territory.

He opposes unilateral moves.

"Israel needs to choose a direction of unification, connection and hope — or of extremity," Gantz told Israel's army radio on Monday.

Gantz has sought to overcome Netanyahu's experience and achievements by allying with two other former military chiefs of staff and ex-finance minister Yair Lapid to form his Blue and White alliance.

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Neck-and-neck

Opinion polls have given Netanyahu's Likud and Blue and White a similar number of seats in the 120-seat parliament, with both far short of an outright majority.

If polling trends hold, Netanyahu would be best placed to build a coalition thanks to smaller right-wing parties allied to him.

But there have been repeated warnings about opinion polls' unreliability in the past.

Should Netanyahu win, he will be on track to surpass founding father David Ben-Gurion as Israel's longest-serving prime minister later this year.

He has been premier for a total of more than 13 years.

But if he does triumph, "King Bibi," as some have called him, faces the prospect of becoming the first sitting prime minister to be indicted.

The attorney general has announced he intends to indict Netanyahu for bribery, fraud and breach of trust pending an upcoming hearing.

He is not required to step down if indicted, only if convicted with all appeals exhausted.