In a nationwide address on Sunday (early Monday AEST), Yamina party leader Naftali Bennett said he had decided to join forces with the country’s Opposition Leader, Yair Lapid.
The pair have until Wednesday to complete a deal in which they are expected to each serve two years as prime minister in a rotation deal.
“It’s my intention to do my utmost in order to form a national unity government along with my friend Yair Lapid, so that, God willing, together we can save the country from a tailspin and return Israel to its course,” Mr Bennett said.
A unity government would end the cycle of deadlock that has plunged the country into four inconclusive elections over the past two years.
It also would end, at least for the time being, the record-setting tenure of Mr Netanyahu, the most dominant figure in Israeli politics over the past three decades.
Mr Bennett, a former Netanyahu aide turned rival, said he was taking the dramatic step to prevent yet another election.
While sharing the Prime Minister’s nationalist ideology, Bennett said there was no feasible way for the hard-line right-wing to form a governing majority in Parliament.
“A government like this will succeed only if we work together as a group,” he said.
He said everyone “will need to postpone fulfilling all their dreams. We will focus on what can be done, instead of fighting all day on what’s impossible.”
Each of the past four elections was seen as a referendum on Mr Netanyahu — who has become a polarising figure as he stands trial on corruption charges — with each ending in deadlock.
He is desperate to stay in power while on trial. He has used his office as a stage to rally support and lash out against police, prosecutors and the media.
If his opponents fail to form a government and new elections are triggered, it would give him another chance at seeing the election of a Parliament that is in favour of granting him immunity from prosecution.
But if they succeed, he would find himself in the much weaker position of Opposition Leader and potentially find himself facing unrest in his Likud party.
Mr Netanyahu, who has accused Mr Bennett of betraying the Israeli right-wing, planned a televised statement later on Sunday (Monday AEST).
In order to form a government, a party leader must secure the support of a 61-seat majority in Parliament. Because no single party controls a majority on its own, coalitions are usually built with smaller partners.
As leader of the largest party, Mr Netanyahu was given the first opportunity by the country’s figurehead president to form a coalition. But he was unable to secure a majority with his traditional religious and nationalist allies.
Mr Netanyahu even attempted to court a small Islamist Arab party but was thwarted by a small ultranationalist party with a racist anti-Arab agenda. Although Arabs make up some 20 per cent of Israel’s population, an Arab party has never before sat in an Israeli coalition government.
After Mr Netanyahu’s failure to form a government, Mr Lapid was then given four weeks to cobble together a coalition. He has until Wednesday to complete the task.
Mr Lapid already faced a difficult challenge, given the broad range of parties in the anti-Netanyahu bloc that have little in common. They include dovish left-wing parties, a pair of right-wing nationalist parties, including Bennett’s Yamina, and most likely the Islamist United Arab List.
But with Wednesday’s deadline looming, negotiations have kicked into high gear. Mr Lapid has reached coalition deals with three other parties so far. If he finalises a deal with Bennett, the remaining partners are expected to quickly fall into place.