Habib Essid will be formally tasked with forming a government later Monday by President Beji Caid Essebsi, their Nidaa Tounes party said.

He will then have a month, extendable once, to win approval for his line-up in parliament, in which the party holds only 86 of the 217 seats after October's landmark election.

Essid, 65, was a top interior ministry official under Ben Ali's iron-fisted regime but was kept on after the 2011 revolution that inspired the Arab Spring.

After a stint as interior minister, he served as security adviser to Islamist Prime Minister Hamadi Jebali.

"After consultations, both within the party and with other parties, there is consensus around the name of Habib Essid as candidate for the post of head of government," Nida Tounes vice president Mohamed Ennaceur told reporters.

President of the Tunisian Assembly, Mohamed Ennaceur (R), and General Secretary of Nidaa Tounes Party, Taieb Baccouche, speak to the press after presenting a paper proposing the name of a new prime minister to newly-elected President Beji Caid Essebsi in Carthage Palace in Tunis on January 5, 2015. The anti-Islamist Nidaa Tounes party of Tunisia's new President Beji Caid Essebsi said it has proposed for the post of Prime Minister Habib Essid, a former interior minister under the deposed dictator Ben Ali. AFP

"He is an independent figure... who has skills and experience," Ennaceur said, singling out his "knowledge of security matters."

Since the revolution, Tunisia has seen a rise in extremism and tackling it will be one of the main challenges facing Essid's government.

The prime minister designate will need the support of other parties in parliament for his line-up.

The moderate Islamist Ennahda party, which holds the second largest number of seats, has not ruled out joining a coalition with Nida Tounes.