Israel votes Tuesday in its second election in five months to determine 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. 

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

Polls open at 7:00 am (0400 GMT) and close at 10:00 pm (1900 GMT) in most areas. Some 6.4 million people are eligible to cast ballots. 

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

Some 18,000 police, security guards and volunteers will be deployed. 

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

Netanyahu enters the election after having suffered one of the biggest defeats of his political career after the April vote. 

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

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