Israeli President Reuven Rivlin has granted Prime Minister Benjamin Netanyahu an extension of 14 days to form a new government.

"I am giving you another 14 days to put together a government," Rivlin told Netanyahu in remarks broadcast live on Israel's main radio stations after the premier formally requested an extension.

After a surprise election victory, Netanyahu was on March 25 tasked by Rivlin with forming the next government and given 28 days to do so, a period which expires this week.

Ahead of the deadline, Netanyahu went early Monday to Rivlin to formally request an extension of up to two weeks.

Despite nearly four weeks of intensive negotiations, Netanyahu has not yet managed to reach agreement on the government he was hoping to form, which would comprise six rightwing and religious parties and have a majority of 67 in the 120-seat parliament.

If he is unable to form a coalition in the next fortnight, Rivlin can assign another party leader to the task, again with a 28-day deadline.

If that fails, he can select a third person who has just 14 days to complete the task. Should that end in failure, Rivlin would call a new election.