Opinion polls published before the weekend suggest that the centre-left Zionist Union is likely to win the most seats.
Israelis head to the polls Tuesday in a vote seen as a referendum on embattled Prime Minister Benjamin Netanyahu, who ruled out a Palestinian state as part of a last-ditch appeal to right-wing voters.
Around six million Israelis are eligible to take part in the vote to elect 120 deputies for the Knesset, or parliament, with polling stations due to open at 7:00 am (0500 GMT).
The ballot to choose Israel\’s 20th parliament came about after Netanyahu, 65, called snap elections late last year as his fractious coalition government teetered on the brink of collapse.
It will be Israel\’s third election since 2009 and the biggest challenge for Netanyahu, who is seeking a third consecutive term.
The veteran rightwing leader is not certain to come first in the vote, with the final opinion polls Friday giving the centre-left Zionist Union led by Isaac Herzog a 3-4 seat lead over Netanyahu.
But the surveys also show Netanyahu will have an advantage when it comes to piecing together a coalition with smaller allies from the right.
Netanyahu has warned a vote for Zionist Union could endanger Israel\’s security and lead to the division of Jerusalem and the establishment of a Palestinian state in the annexed eastern sector.
On Monday he was asked by the rightwing NRG website if it was true that there would be no Palestinian state established if he was reelected.
"Indeed," said Netanyahu, who in 2009 had endorsed the idea of two states living side by side.
He later told public radio the two-state solution was now irrelevant, saying the "reality has changed" and "any territory which would be handed over would be taken over by radical Islamists".
The new premier will have to deal with a series of daunting domestic and foreign policy challenges including Iran\’s nuclear programme, repairing ties with the United States and maintaining economic growth.
And then there are the tricky issues of ties with the Palestinians following the collapse of peace talks last year, instability left over from the 2014 Gaza war and a looming legal challenge at the International Criminal Court.
There are 25 lists battling it out for seats, in a reflection of Israel\’s diverse political map, but only 11 are forecast to enter the Knesset.
Under Israel\’s proportional representation system, any party can enter parliament if it receives more than 3.25 percent of the vote.
By law, the final election results must be published within eight days of the vote, but a spokesman for the Central Elections Committee told AFP the counting would be finished on Thursday afternoon.
Under Israel\’s complex electoral system, the task of forming a new government does not automatically fall to the party with the largest number of votes, but to the MP or party leader with the best chance of cobbling together a coalition with a parliamentary majority of 61.
Once the results are known, President Reuven Rivlin has seven days to entrust a party leader with the job of forming the next government.
"The president has made clear that Israel needs a government as soon as possible, and therefore is keen to begin consulting with the parties\’ representatives as soon as possible," a spokesman said.
As in previous elections, Netanyahu has framed himself as the only candidate capable of protecting Israel from Iran and the threat of Islamic extremism.
But a bellicose address to the US Congress this month in which he pilloried nuclear talks between world powers and Tehran appears to have made little impact.
"It has been a while since Israelis wanted a \’strongman\’; we want the next leader to be charismatic and to solve problems," said analyst Tamir Sheafer.
Netanyahu\’s only realistic challenger is Herzog, who in pushing for social justice and fresh talks with the Palestinians is offering voters a stark alternative.
The last time Israel elected a Labour leader was in 1999.
Exit polls are due to be released shortly after voting at more than 10,000 polling stations close at 2000 GMT, with the main results due out early on Wednesday.