Mr Barak forced the early election by submitting his resignation last December.
But the latest opinion polls confirm that the Labour leader appears to be heading for almost certain defeat at the hands of right-winger Ariel Sharon of the Likud party.
Mr Barak forced the early election by submitting his resignation last December.
Violence continued on Monday with one Israeli soldier killed and a Palestinian boy wounded in the Gaza Strip.
'Dangerous extremist'
In the final days of campaigning, Mr Barak has tried to portray his rival as a dangerous extremist who would lead Israel into a new conflict with its neighbours.
"We must decide if between us and peace there will be another bloody war, its outcome unknown," Mr Barak wrote on the front page of top-selling daily Yediot Aharanoth.
But a poll published in the same paper on Monday showed Mr Sharon to have an 18 percentage point lead over Mr Barak, consistent with other polls in recent weeks.
Mr Sharon's advisers have tried to soften the former general's battle-hardened image with a relatively low-key campaign.
In a final television appearance on Sunday, he spoke about his grandchildren and his hopes for their future.
''In what kind of Israel will these children grow up?'' he asked.
'If I'm elected, I shall do everything and a little more... to bring about quiet, security and peace.''
In an newspaper article on Monday, however, the Likud leader repeated his campaign theme that he would not negotiate a peace deal as long as the four-month Palestinian uprising continues.
Orthodox blow
He has pledged time and again not to give up any more land in the West Bank and not to divide Jerusalem.
And although he has criticised his opponent for making too many concessions to the Palestinians, he says he will invite Mr Barak to join a government of unity.
Israeli soldiers at military bases and those helping with earthquake relief in India have already cast the first votes.
Over the weekend, Mr Barak appealed to Russian immigrants for support as well as Israeli Arabs who are threatening to boycott the election.
But, in a fresh blow to the prime minister's campaign, Mr Sharon on Sunday won the backing of ultra-Orthodox religious parties.
Election-eve shootings
In fresh violence on Monday, an Israeli soldier was shot dead near the Rafah refugee camp in the south of the Gaza Strip.
An army spokesman said the soldier was killed by a single bullet while driving an armoured vehicle.
Israeli soldiers shot and wounded a 13-year-old Palestinian boy when they fired on stone throwers near the Karni crossing point that links Israel and the Gaza Strip.
Militant groups and Palestinian leader Yasser Arafat's Fatah faction have called for a 'day of rage' on Tuesday to coincide with the election.
The main issue of the campaign has been the Palestinian revolt against Israeli rule and how to handle it.
More than 375 people, the vast majority of them Palestinians, have died in the violence since September.