Interim Prime Minister Hamadi took the action after thousands of people turned out to protest following the shooting death of Chokri Belaid, general secretary of the Democratic Patriotic Party, as he was leaving his house in the capital, TAP said.
Jebali said the new government's mission would be to guide the country's affairs until elections can be held in the country where the so-called Arab Spring started, state news agency TAP reported.
"All ministers and secretaries of state in the forthcoming mini government of technocrats will not run for next elections," he said.
Press TV reported four Tunisian opposition parties had quit the country's Constituent Assembly and called for a nationwide strike. The four parties were the Republican Party, Call of Tunisia, al-Massar and the Popular Front, the Iranian network said.
Euronews reported President Moncef Marzouki, who returned home from Strasbourg, France, where he was attending meetings ahead of a summit in Cairo, said Belaid's assassination represented "a conspiracy against Tunisia" meant "to threaten the country's security and stability and sow disorder."
He expressed confidence the country's security forces would find those responsible and called on politicians to show patience and wisdom during the crisis.
Interior Minister Ali Larayedh said after an emergency Cabinet meeting there were no plans "for the moment" to invoke a curfew in the country.
Demonstrators gathered in front of the Interior Ministry to mourn Belaid, chanting, "We are all Chokri," "O Chokri, O martyr, we will follow your path," and "Terrorism, bullets, Tunisians are fearless," Tunisia Live reported.
Police said indications were two people were involved in the assassination, Larayedh said on a Tunisian radio station.
Belaid was a leader of the opposition Popular Front, which formed in October to counter the government. He has become a chief critic of Ennahda, the moderate Islamic party leading the government in a coalition with two secular parties.
Even though it has offered assurances it would respect liberal democratic values, Ennahda has been criticized for its leniency toward the ultraconservative Salafis, The New York Times reported.
The protesters Wednesday also shouted anti-Ennahda slogans, such as "Ghannouchi [Ennahda founder], you are a predator" and "Bring down the oppressor of the people, bring down the Brotherhood party."
Belaid recently accused Ennahda supporters and Salafists of attacking a meeting of his party's members Saturday.
"At the end of our meeting, a group of Ennahda mercenaries and Salafists attacked our activists," Belaid said.
No one immediately claimed responsibility for the attack, which the government called an "odious crime." Its cause remained unclear.