Tunisia's president, himself just elected, appointed Hamadi Jebali, the secretary-general of Ennahda Party which dominated October's elections, to form the interim government.
Under the new system, executive power will be centered on the prime minister who has three weeks to present his choices for the assembly's approval.
Samir Dilou, a leading member of the party, said he expected that period to be substantially shortened, perhaps even by week's end so that urgent economic issues can be tackled.
For now, the outgoing interim government formed after President Zine Abidine Ben Ali fled, will manage the affairs of state. Tunisians overthrew Ben Ali in January, sparking pro-democracy protests across the Arab world.
