Israeli law says that after the first four weeks of political bargaining a further 14 days is granted by the president on request.
"At the end of the meeting, the president acceded to the prime minister's request and granted him a further two weeks to form a government," a statement from the presidency said in English.
Netanyahu's Likud party won 35 seats in the April 9 general election, with most parties represented in the 120-seat parliament recommending that he form the next governing coalition.
On April 17 Rivlin formally tasked him with the mission.
Such negotiations generally run close to the wire as parties seek to extract the maximum in cabinet portfolios and other forms of political clout.
Netanyahu on Sunday told cabinet ministers that this time there had been outside influences on the progress of talks, citing public and religious holidays and a Gaza flare-up.
Four Israeli civilians and 25 Palestinians, including at least nine militants, were killed in the two-day flare-up, which ended on Monday in a tentative truce.
The emerging coalition is expected to include the 16 members of the ultra-Orthodox Jewish parties as well as the far-right national religious union, Avigdor Lieberman's nationalistic Israel Beitenu and the centre-right Kulanu.
Netanyahu's lawyers were meanwhile negotiating with the justice ministry on a date for pre-trial hearings on pending corruption charges.
The attorney general announced in February his intention to indict Netanyahu for bribery, fraud and breach of trust -- pending a hearing.
Netanyahu is not required to resign if indicted, only if convicted with all appeals exhausted.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)