Israel's incoming Prime Minister Benjamin Netanyahu signed up enough parties for a coalition with a parliamentary majority on Thursday but requested more time to present the new government, citing a need to agree on roles for his designated partners.

Netanyahu was tasked with forming a government after his conservative Likud and likely religious-nationalist partners triumphed in a Nov. 1 election. That mandate is due to expire on Sunday.

In a letter to President Isaac Herzog that Likud circulated to the media, Netanyahu requested the full 14-day extension allowed by law. Herzog's office had no immediate response.

"Some issues related to roles have yet to be agreed upon" in coalition negotiations, Netanyahu wrote in the letter.

The centrist opposition has urged Herzog not to grant an extension, accusing Netanyahu of buying time to pass controversial legislation. One such bill would enable Arieh Deri of the ultra-Orthodox Jewish party Shas to serve in the cabinet despite his criminal record.

Earlier on Thursday, Likud said in a statement saying it had reached a coalition deal with Shas, making it the fifth party to join Netanyahu and giving him comfortable control of 64 of the Knesset's 120 seats.

"We have completed another step towards the formation of a right-wing government that will act to serve all of Israel's citizens," Netanyahu said in the statement.

According to the agreement, Deri will head the interior and health ministries during the first half of the government's term, then take up the Finance Ministry in the second half. Deri will also serve as deputy prime minister under Netanyahu.

Deri, a veteran politician, was convicted of tax fraud last year but spared jail in a plea deal. His inclusion in the new government, alongside two far-right parties run by hardline West Bank settlers, has stirred concern in Israel and abroad.