The coalition led by Prime Minister Naftali Bennett, which unseated veteran premier Benjamin Netanyahu in June, needed to pass a budget by November 14 to ensure its survival and avert a fifth election in three years.

The coalition that counts on support from right-wingers, centrists, leftists and Islamists controls just 61 of the 120 seats in Israel's parliament, the Knesset, meaning it cannot sustain any defections.

It passed a key hurdle as it approved a 609-billion shekel ($194-billion) spending plan for 2021 in overnight votes.

"Celebration day for the state of Israel," Bennett, a right-wing religious nationalist, tweeted after the vote.

"After years of chaos, we have formed a government, we have conquered Delta (variant of the coronavirus) and now, praise God, we have passed a budget for Israel."

But Bennett's government has presented a two-year budget bill and was enduring another marathon day of voting on its 573-billion shekel package for next year.

Foreign Minister Yair Lapid, the centrist who was the main architect of the coalition that brought down Netanyahu, had forecast that Thursday would be a "long day".

The chamber was trudging through hundreds of separate votes on individual spending measures with more than 150 left to be decided by the evening.

Amid the laborious voting process, Netanyahu mistakenly voted with the government six times, tweeting after: "It can happen that you get confused when voting. Ask anyone who voted for Bennett."

In a selfie posted on Twitter, a bleary-eyed Defence Minister Benny Gantz wrote that even if his "fatigue is noticeable" he was "proud of every click" that moved the coalition towards a two-year budget.

'Highly likely'

Commentators said the ease and relative speed with which the 2021 budget passed showed that the coalition could hold together even with its deep ideological differences and its wafer-thin majority.

Hebrew University political scientist Yonatan Freeman told AFP it was "highly likely" the 2022 budget would now also be passed.

Approval of 2022 spending is particularly crucial for the four-year coalition because it stabilises the alliance up to the period when Bennett is due to turn the premiership over to Lapid in 2023.

Any suggestion that the government might fall before Lapid takes power under the power-sharing deal would unsettle the coalition's left wing, Freeman explained.

Israel's three-year failure to pass a budget is a symptom of the unprecedented political gridlock that plagued the country from December 2018 until when Bennett's government was sworn in.

Netanyahu in the wings

It took until 5 am (0300 GMT) for parliament to complete the vote on the 2021 budget with hundreds of spending measures requiring individual votes through the night.

There had been fears the process might be thwarted with now opposition leader Netanyahu playing the role of spoiler for the government that finally brought an end to his 12 straight years in power.

Netanyahu addressed lawmakers during the debate, accusing Bennett of leading "a government of liars".

"We must bring down this irresponsible government," he told MPs.

His failure to do so could trigger increased calls for a leadership change within his party, experts said.

"The passage of the budget will weaken Netanyahu's hold on the Likud party," Freeman said.

It was a budget deadlock that sank the last, short-lived coalition led by Netanyahu and his alternate premier Gantz.

Gantz accused Netanyahu of deliberately blocking the budget's passage in December last year to force an election, which the premier hoped would secure him and his right-wing allies an outright majority.

But Netanyahu came up short in the March vote for the fourth time in two years, paving the way for Bennett and Lapid to forge a coalition.