Incumbent Prime Minister Benjamin Netanyahu's aggressive style has strained relations with Israel's foreign partners -- including closest ally the United States -- leaving the Jewish state increasingly isolated.
For Netanyahu's supporters, the premier's take-it-or-leave-it approach has been essential to ensuring Israel's continued security.
But critics, including the centre-left Zionist Union headed by Labour chief Isaac Herzog which polls show is likely to win the vote, say the time has come for Israel to put the diplomatic back in its diplomacy.
"Wanted: A prime minister who can clean up Israel's diplomatic mess," left-wing daily Haaretz headlined a story on Thursday.
Among the challenges facing the next government are an unprecedented crisis in ties with Washington, a legal-diplomatic confrontation with the Palestinians, a looming international nuclear deal with Iran and tensions with Europe over settlements.
The already-frosty relationship between Netanyahu and US President Barack Obama took a nose-dive this month after the Israeli leader insisted on addressing Congress to air concerns over a deal between world powers and Iran over its nuclear programme.
"The price of publicising the issue and weighing on the public debate, which was attained through the Congress speech, is the loss of influence behind closed doors," said Yigal Palmor, a former spokesman for Israel's foreign ministry.
Experts believe a new Herzog-led government would definitely help the process of rebuilding ties with the Obama administration.
- Europeans waiting -
But if Netanyahu returns, he will face greater obstacles in coordinating with Washington, not only over Iran, but on a variety of issues on which the US would normally have provided unwavering support, said professor Eytan Gilboa, an expert on US-Israel relations from Bar Ilan university.
One such issue is the Palestinian effort to unilaterally advance their statehood bid through the United Nations and legal action against Israel at the International Criminal Court.
"In the past, you could trust on the US blocking them, but with a narrow (rightwing) government -- the conditions will change," Gilboa said.
There is also the question of Israel's relationship with the European Union, its biggest trading partner, with foreign policy chief Federica Mogherini seeking more involvement in resolving the Israeli-Palestinian conflict.
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Europe is in the process of cancelling tax exemptions on Israeli products made in settlements in the occupied West Bank and mulling plans to label the origin of others.
For now, the process has been delayed, both because of the complexity of the issues and the election, experts said.
"The Europeans didn't wish to appear as though they were intervening in the elections," said Sharon Pardo, director of Ben Gurion University's Centre for Study of European Politics and Society.
"Their feeling is that if these measures were implemented or advanced, it would help the Israeli rightwing, which would have claimed they were acting against Netanyahu's government," he said.
Ties with Europe may also improve if a new leadership is voted in, he said.
"There is no doubt that if the next government is comprised of elements considered by Europe as more moderate, we'll see less European speed (on the issue) and more willingness to listen to the government," he said.
- The trickiest issue -
What is likely to prove the most difficult issue is resurrecting peace efforts with the Palestinians, which collapsed in April 2014.
Israel says the process failed because the Palestinians refused to accept a US framework document outlining the way forward.
But the Palestinians blame the collapse on Israel's settlement building and the government's refusal to release veteran prisoners.
Dore Gold, a former ambassador to the UN who served as foreign policy adviser to Netanyahu until January, said whoever leads the next government will face pressure to return to the negotiating table -- with world powers leaning on Israel to make concessions.
"The West always wants Israel to pay a price to resume negotiations with Palestinians," he said, referring to a freeze on settlement construction or the release of prisoners. "That is unfortunate."
Although Herzog has said his Zionist Union would seek to revive the diplomatic process with the help of moderate regional allies, Netanyahu has recently made clear that the time was not right for any agreement involving territorial concessions.
For Palmor, now head of public affairs at the Jewish Agency, even without a return to peace talks, Israel should work to calm the situation with the Palestinians in order to foster conditions under which talks could eventually resume.
"Given the lack of direct negotiations with the Palestinians, Israel has to seek quiet -- not a solution -- but some form of calm on the Palestinian front, some sort of balance that will in due time allow a resumption of diplomatic efforts for a negotiated agreement," he said.