Riot-torn Tunisia is poised for the announcement of a new government amid hopes of a peaceful fresh start for the nation.

Dozens of people have died in a month of clashes that were initially between police and protesters angry about repression and corruption but now appear to be between police and Ben Ali loyalists, and Prime Minister Mohamed Ghannouchi said on state TV that a national unity government will "most certainly" be named "to open a new page".

There are three legal opposition parties that could be included in the government Mr Ghannouchi has been directed to form by interim president Fouad Mebazaa.

However, worries among Tunisians grew with continuing violence and worsening shortages of essentials such as milk, bread and fresh fish.

Major gun battles erupted on Sunday outside the palace of deposed president Zine El Abidine Ben Ali in the centre of Tunis and in front of the main opposition party headquarters as authorities struggled to restore order.

Police arrested dozens of people, including the top presidential security chief, as tensions appeared to mount between Tunisians buoyant over Ben Ali's departure and loyalists in danger of losing major perks.

There were cheers and smiles in much of the capital as residents tore down the massive portraits of Ben Ali, some of them several storeys high, that hung from lampposts and billboards and were omnipresent during his 23-year reign.

The presidential palace gun battle in Carthage involved the army and members of the newly appointed presidential guard fighting off attacks from militias loyal to Ben Ali.

Residents of Carthage - a centre of power in ancient times but now a Tunis suburb popular with tourists - said they have barricaded themselves inside their homes amid the shooting. Many soldiers were in the palace, but it was unclear whether any of the interim government's leaders were.

Security chief Ali Seriati and his deputy were charged with a plot against state security, aggressive acts and for "provoking disorder, murder and pillaging," the state news agency reported.