TUNIS (AFP) - Prime minister-designate Mehdi Jomaa said on Sunday he was asked anew by the President to form a government to steer Tunisia out of crisis after an initial failure.

Mr Jomaa had been expected to submit his lineup to President Moncef Marzouki on Saturday but shortly after midnight he announced his failure to form a new government.

"The president has once again placed his trust in me and tasked me with forming the government," said Mr Jomaa in remarks broadcast by state television, after talks with Mr Marzouki.

"We have taken a big step towards forming the government. It is almost ready and, inshallah (God willing), I will not take much time in submitting the lineup to the President," he added.

But in a sign that Tunisia's political class remains deeply divided, the technocrat prime minister chosen last month to steer the country towards fresh elections announced after missing Saturday's deadline that he had failed to muster sufficient consensus for a new caretaker Cabinet.

Under Tunisian law, Mr Jomaa now has another 15-day period to form a government which then must win a vote of confidence in Parliament.

Mr Jomaa was industry minister in the outgoing government led by the Islamist Ennahda party and has been tasked with forming a government of independents to end the crisis which has gripped Tunisia since the assassination last year of two opposition MPs by suspected jihadists.

Several Tunisian media outlets said the main sticking point in the negotiations to form a new government was the identity of the interior minister.

Some opposition groups want incument minister Lotfi Ben Jeddou removed because he served in the Ennahda government.

But others, not only Ennahda supporters, argue that a volatile security situation across the North African country means that continuity is needed at the interior ministry.

The latest developments come as Tunisia's 217-seat interim Parliament, in which Ennahda holds the majority, is due to approve on Sunday a much-delayed Constitution.

The vote, initially announced for Saturday, was pushed back until Sunday to allow lawmakers to reform the rules of a confidence vote in a new government.