JERUSALEM — Israel moved closer on Wednesday to another early election, its fourth in two years, after Prime Minister Benjamin Netanyahu’s disenchanted coalition partners joined the opposition in a preliminary vote to bring down the unity government in which they serve.

The bill to disperse the 120-seat Knesset, or parliament, and head to new elections heralded a new period of political instability and upheaval even though the government did not immediately fall. The motion passed 61 to 54 with five lawmakers absent, but it must now go to committee and pass three more readings before it becomes law.

In any case, if a state budget is not approved by Dec. 23, the Knesset will disperse automatically and elections will be set for late March. Mr. Netanyahu has so far refused to pass a budget for 2020 or to present one for 2021.

Billed as an emergency coalition, the government was ostensibly formed to fight the public health and economic crises posed by the coronavirus pandemic. Instead, it has largely been paralyzed amid infighting over the long-delayed approval of a state budget while appointments to key vacant positions in the government and public sector have been frozen.

“These last months have been difficult,” Yair Lapid, the leader of the opposition, said in a speech introducing the bill. “They haven’t only been difficult because of the health crisis. They haven’t only been difficult because of the economic disaster. They’ve been difficult because of the depth of the failure of this government.”

The government was sworn in just six months ago, after three inconclusive elections ended without any one candidate able to muster a parliamentary majority. In the end, Mr. Netanyahu of the conservative Likud party persuaded his main rival, Benny Gantz, a former army chief and the leader of the centrist Blue and White party, to join forces with him in a unity government.

Mr. Gantz, who broke an election promise by joining Mr. Netanyahu’s government and has since lost much of his public support, voted on Wednesday to break it up.

Israel is just emerging from a second national lockdown, but with infections rising again, health experts were already warning of a third.

Israeli analysts have predicted for months that Mr. Netanyahu would back early elections rather than see Mr. Gantz take over as prime minister a year from now, as laid out in their coalition agreement. Few people, including Mr. Gantz, expected that to actually happen.

Likud lawmakers have openly declared that Mr. Gantz no longer commands enough public support to serve as prime minister.

With a trial on corruption charges expected to enter the evidentiary phase in February, Mr. Netanyahu is clinging to power so he can fight the case from the advantage of high office. A new election could strengthen his position.

Recent opinion polls put Likud firmly in the lead and indicate that Mr. Netanyahu could even put together a right-wing-religious coalition that could provide him with immunity from prosecution.

The opposition would be entering an election campaign weakened and splintered.

Mr. Gantz and Mr. Netanyahu have blamed each other for the coalition crisis.

“Netanyahu didn’t lie to me — he lied to all of you,” Mr. Gantz said in an angry televised address on Tuesday night. “He didn’t lead me astray. He led the entire nation astray.”

He added: “Netanyahu is on a path of personal survival. The only index for his decision-making is relevance to his ability to evade trial, which is just around the corner.”

In a video statement issued shortly before Mr. Gantz’s speech, Mr. Netanyahu said, “I’ve been saying for a long time, this is not the time for elections — this is the time for unity.” He accused Mr. Gantz of establishing “a government within the government.”

Despite his vote with the opposition to bring down the government, Mr. Gantz left the door open for a deal, saying the government would be saved if a budget were approved by the Dec. 23 deadline.

Some lawmakers said talks were underway to form an alternative government without elections, though the chances were slim that any other coalition could be established and command a majority in Parliament.

In the topsy-turvy world of Israeli politics, Mr. Netanyahu’s and Mr. Gantz’s votes on Wednesday were not necessarily indicative of their true positions.

Mr. Netanyahu is pushing for elections but voted against the bill to disperse the Parliament, wary of being blamed for the early vote, said Yohanan Plesner, the president of the Israel Democracy Institute, a nonpartisan research organization in Jerusalem. Mr. Gantz voted for it, though he is fearful of elections, Mr. Plesner added.

Mr. Gantz is “in a conflict of interest,” Mr. Plesner said, because he does not want to show more weakness by giving into Mr. Netanyahu. By voting against his own government, Mr. Plesner said, Mr. Gantz did “cross a threshold.”