* Voters consider "King Bibi" versus "Bibi fatigue"
* Novice ex-general Gantz could stop fifth term for Netanyahu
* Victory will require parliamentary bloc-building (Adds comments by Netanyahu, Abbas)
By Jeffrey Heller and Dan Williams
JERUSALEM, April 9 (Reuters) - Israelis voted on Tuesday as Prime Minister Benjamin Netanyahu tried to galvanise supporters by playing up the prospects of his strongest rival, an ex-general who has pledged clean government, to deny him a fifth term.
Netanyahu, in power consecutively since 2009 after a first term from 1996 to 1999, is fighting for his political survival. He faces possible indictment in three corruption cases in which the right-wing leader has denied any wrongdoing.
Final opinion polls on Friday showed Netanyahu, who heads the Likud party, falling behind his main rival, former military chief Benny Gantz of the Blue and White faction, but with an easier path to form a government.
If he wins, Netanyahu, 69, will achieve a record fifth term and become Israel's longest-serving prime minister this summer after a contest that will determine whether the man some Israelis hail as "King Bibi" had fallen victim to "Bibi fatigue".
Israelis were casting ballots for a party's list of parliamentary candidates. No single party has ever won a ruling majority in parliament in an election in Israel, meaning that coalition-building after the vote, a process that could take weeks, will determine the winner.
Voting ends at 10 p.m. (1900 GMT). TV stations will immediately publish exit polls giving a preliminary indication of the number of Knesset seats parties have won and which leader stands the best chance of piecing together a government.
During the campaign, the rival parties accused each other of corruption, fostering bigotry and being soft on security.
Netanyahu highlighted his close relationship with U.S. President Donald Trump, who delighted Israelis and angered Palestinians by recognising Jerusalem as Israel's capital in 2017 and moving the American Embassy to the holy city last May.
In a rare turn during the race towards the Israeli-Palestinian conflict, Netanyahu further alarmed Palestinians by promising to annex Jewish settlements in the occupied West Bank if re-elected. Palestinians seek a state there and in the Gaza Strip, with East Jerusalem as its capital.
Commenting on the Israeli election, Palestinian President Mahmoud Abbas told reporters in the West Bank: "We hope they choose the just path, in the right direction, to reach out for peace."
Israeli-Palestinian peace talks collapsed in 2014.
SAVE ME, NETANYAHU TELLS BEACH-GOERS
Election Day is an official holiday in Israel, and Netanyahu paid a visit to the Mediterranean seashore near Tel Aviv to urge beach-goers to head to the polling stations and vote for him.
Otherwise, he said in a beach video he posted on Twitter, Likud supporters enjoying a day out will "wake up tomorrow morning" and find a "left-wing" prime minister in his place from Gantz's party.
In a further tweet, Netanyahu said he was calling an emergency meeting with his campaign officials to discuss what he described as lower voter turnout in Likud strongholds compared with a strong voting percentage in "left-wing bastions".
Political commentators have dubbed similar warnings by Netanyahu as a "gevalt" strategy, a Yiddish expression of alarm, aimed at motivating complacent supporters.
The Central Elections Committee put overall turnout, some four hours before polls close, at 2.5 percent lower than at the same time during the previous national ballot in 2015.
Once the votes are tallied, President Reuven Rivlin will ask political parties that have won parliamentary seats who they support for prime minister. He will then pick a party leader to try to form a coalition, giving the candidate 28 days to do so, with a two-week extension if needed.
Casting his vote in Rosh Ha'ayin near Tel Aviv, Gantz, 59, said: "This is a day of hope, a day of unity. I look into everyone's eyes and know that we can connect."
One factor may be the turnout of voters from Israel's 21 percent Arab minority. Many were angered by Israel's nation-state law, passed in 2018, which declared that only Jews have the right of self-determination in the country. Netanyahu supported the legislation.
Netanyahu's party sent monitors equipped with body cameras to a number of polling stations with Arab constituents on election day. Arab politicians condemned the move as voter intimidation.
Voting near Tel Aviv, gynaecologist Yaron Zalel, 64, said he supported Gantz. "Netanyahu did a lot of great things for Israel, really, a lot of great things. But he is 13 years in power and enough is enough," he said.
Backing Netanyahu at the same polling station, Avi Gur, 65, a lecturer at Ariel University in a settlement in the West Bank, said he was "very excited".
"I hope that rightism will win," he said. (Writing by Jeffrey Heller and Dan Williams; Additional reporting by Rami Ayyub in Rosh Ha'ayin; Ron Bousso and Rawan Sheikh Ahmad in Haifa; Rahaf Ruby and Stephen Farrell in Jerusalem Editing by Larry King and Giles Elgood)
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