Details added (first version was published at 21:31)
Tunisia's acting president Foued Mebazaa, the former speaker of the parliament, said he has asked Prime Minister Mohammed Ghannouchi to form a coalition government, Dubai-based al-Arabiya TV reported.
In a televised speech, Mebazaa said the ultimate national interest requires the formation of a national unity government, Xinhua reported.
The move is seen as an attempt to save the government from a political mishap, as president Zine El Abidine Ben Ali was ousted Saturday and fled to Saudi Arabia after riots hit the country.
Mebazaa's call for a national unity government won support from Tunisian opposition leaders who said there is an imminence need for setting up a unity salvation government to end unrest that gripped the country.
The Tunisian government has declared a state of emergency, banning any gathering involving more than three people.
"We appeal to all political factions to work on forming an all- out, urgent and national government," a senior member of the Unionist Democratic Union (UDU) told the TV.
Premier Ghannouchi has told Al-Jazerra TV that exited opposition figures are welcome to return to Tunisia.
"All political opposition figures, who live in exile, can return to homeland without any fears of harassment or legal charges," he said.
This came as Saudi Arabia said deposed president Ben Ali is now in the kingdom, saying he and his family are welcome in the country and this move was taken due to "exceptional circumstances hit Tunisia".
But a leading Saudi journalist said Ben Ali will not be allowed to do any political role in Saudi Arabia, adding the kingdom stands behind the Tunisians.
Ben Ali will be in Saudi Arabia as "a political refugee" not "a head of state", Jamal Khashoggi told the Dubai-based TV.
"Saudi Arabia will not sanction the ousted president to give political statements, do any political activities nor make contacts to arrange his situation back home," he said.