JERUSALEM -- Civil unrest between Jews and Arabs in Israel dealt a strong blow to efforts by Prime Minister Benjamin Netanyahu's opponents to unseat the Israeli leader after a series of inconclusive elections.

Naftali Bennett, head of the ultranationalist Yamina party, said he was abandoning efforts to form a coalition with centre and left-wing parties to form a new government.

The post-election landscape remains largely the same: Netanyahu was given a chance to form a government, and failed. Now the main anti-Netanyahu bloc led by Yair Lapid's centrist Yesh Atid - 'There is a Future' - party also has no obvious route to putting together a majority in the 120-member Knesset.

Bennett, a rightist who was always an unlikely bedfellow with the more moderate Lapid, said he was abandoning those coalition talks in favour of putting together a wider unity government in the nation's interests at a time of crisis.

It leaves open the very real possibility of another election - an unprecedented fifth in just over two years.

Analysts said the collapse of the Lapid-Bennett partnership in the wake of the violence on Israeli streets may give Netanyahu extra time to make a political move to stay in power.

"From the moment (the fire) was lit, the government of change was dead and Netanyahu came back to life," commentator Ben Caspit wrote in the newspaper Maariv on Friday.

Lapid has three weeks left to try to form a governing coalition. A "rotation" deal in which Lapid and Bennett would take turns as prime minister had been mooted, but it would need the backing of Arab legislators for a parliamentary majority.

Bennett was quoted by Israeli media on Thursday as saying the current strife with Israel's 21 per cent Arab minority would make such a government unfeasible.

Current cross-border hostilities between Israel and Palestinian militants in Gaza have been accompanied by violence in mixed communities of Jews and Arabs in Israel. Synagogues have been attacked and street fights have broken out, prompting Israel's president to warn of civil war.

Mansour Abbas, who heads the United Arab List party, said on Channel 12 TV that Bennett phoned him to say a so-called "government of change" with Lapid was now "off the table."

In a televised address, Lapid voiced regret at Bennett's decision but said he would continue his efforts to put together a coalition.

Israeli political commentators gave him little chance of success.

(Editing by Jeffrey Heller, Howard Goller and Mark Heinrich)