* Request for more time to build coalition not unusual
* Israeli leader's right-wing Likud won March 17 election
* Needs political partners for governing majority
By Jeffrey Heller
JERUSALEM, April 20 (Reuters) - Prime Minister Benjamin Netanyahu will have two more weeks to form a new government after he asked Israel's president on Monday to extend a 28-day period to form a coalition following his election victory.
Netanyahu's right-wing Likud party came out on top in the March 17 election, winning 30 of parliament's 120 seats and defeating its main rival, the center-left Zionist Union led by Isaac Herzog.
Likud has been negotiating with far-right and ultra-Orthodox parties, and with a centrist faction, to form what would be the most right-wing administration in Israel's history. It would control 67 parliamentary seats.
"We made progress and we are on the way to forming a government, but I need additional time for it to be stable and to reach agreements on important issues that will help us meet all the challenges facing Israel," Netanyahu said during a meeting with President Reuven Rivlin.
Rivlin granted him the 14-day extension, as expected.
The request was not unusual in a country where no one party has ever won an outright majority in a parliamentary election and negotiations among potential political partners over cabinet posts and policy have often gone down to the wire.
Netanyahu has largely kept a lid on details of the talks, focusing instead in his public remarks on Israel's opposition to a framework nuclear deal that its main ally, the United States, and five other world powers reached with Iran on April 2.
Political commentators have cited the allocation of cabinet portfolios as the main sticking point in the coalition negotiations.
Their slow pace has raised speculation that Netanyahu, who would serve a fourth term as prime minister, could opt for a broader coalition with Zionist Union.
But Herzog has largely dismissed that possibility, insisting that Zionist Union was keen to embrace a role as opposition leader.
If Netanyahu fails to win the support of at least 61 legislators in the next two weeks - a scenario political commentators see as unlikely - Rivlin can ask another member of parliament to try to put together a government. (Editing by Jeffrey Heller and Angus MacSwan)