Israeli Prime Minister Benjamin Netanyahu has suffered a serious defeat in his bid to stay on as premier by failing to form a new coalition government, but his opponent faced similar difficulties on Tuesday.

Ex-military chief Benny Gantz is now expected to be given the chance to try to negotiate a coalition by President Reuven Rivlin, but a deadlock following polls held on September 17 remains and yet another election cannot be ruled out.

It would be Israel's third election within a year after Netanyahu also failed to form a coalition after April polls.

Netanyahu's decision to inform Rivlin on Monday night that he has been unable to form a government by no means signalled the end of his tenure as Israel's longest-serving prime minister.

He remains premier as long as no new government is formed, and a number of scenarios exist that could see him retain his post even as he faces the possibility of corruption charges in the weeks ahead.

One of the few things clear in Israel's post-electoral morass was that Netanyahu, who celebrated his 70th birthday on Monday, was not giving up.

Copyright Agence France-Presse, 2019