Jerusalem, Dec 9 (IANS): Former Israel Prime Minister Benjamin Netanyahu has asked President Isaac Herzog for an extension of the mandate to form a new coalition government, his Likud party said in a statement.

The Likud formally submitted to Herzog a request for additional 14 days to put together a coalition government, the statement said on Thursday.

The President has yet to announce his decision. If he refuses to approve the request, Netanyahu's 28-day mandate would expire at midnight between Saturday and Sunday, Xinhua news agency reported.

"The negotiations are in full swing and there has been a lot of progress," Netanyahu wrote in the request, adding that he still needs more time to form a new government.

He said the extension is needed because of "remaining issues" with the appointment of some ministers.

Earlier on Thursday, the Likud announced it signed an interim agreement with Shas, a Jewish ultra-Orthodox party, securing a comfortable 64-seat majority in the 120-seat parliament.

Under the deal, Shas Chairman Aryeh Deri will head the Interior and Health ministries for the first half of the government's term before assuming the position of Finance Minister. However, a final coalition agreement has yet to be signed.

Netanyahu signed on Tuesday an interim coalition agreement with the United Torah Judaism, another ultra-Orthodox party, while three ultra-nationalist parties -- the Religious Zionism, Jewish Power and Noam -- already signed full coalition agreements.

Netanyahu, Israel's longest-serving leader, is expected to return to power about a year and a half after he was ousted, thanks to the November 1 parliamentary elections in which he and his far-right partners won a majority.

Outgoing Justice Minister Gideon Sa'ar urged the President not to grant an extension.

"The actual formation of the government has already been completed," Sa'ar wrote on Twitter.