Tunisia's PM Mohammed Ghannouchi has defended the inclusion of members of the old administration in his new unity government in a radio interview.
The retained ministers have "clean hands" and have always acted "to preserve the international interest", he told French radio Europe 1.
The new cabinet is beginning work amid lingering tensions on the streets.
President Zine al-Abidine Ben Ali was overthrown on Friday after a month of protests in which 78 people died.
Mr Ben Ali has sought refuge in Saudi Arabia.
There has been no reaction on the streets so far after the announcement of the unity cabinet that includes familiar faces from the past - Mr Ghannouchi himself is an ally of the former president.
But the BBC's Wyre Davies says pledges to allow political and media freedoms have placated many protesters.
He says the task now will be to move quickly to begin the constitutional reforms and preparation for free and fair elections which Tunisians have been promised.
He says another urgent challenge is to begin to return economic stability to the country - the crisis is estimated to have cost it some $2bn (£1.3bn).
'Total freedom'
In the interview on Tuesday, Mr Ghannouchi vowed that all those involved in repression in Tunisia under the President Ben Ali's regime would face justice.
The foreign, interior and defence ministers all kept their jobs when Mr Ghannouchi unveiled the new administration on Monday - though three prominent opposition figures were named to key posts.
Ahmed Ibrahim, leader of the opposition Ettajdid party, becomes minister of higher education, while Mustafa Ben Jaafar, of the Union of Freedom and Labour, is to serve as health minister.
Najib Chebbie, founder of the Progressive Democratic Party, was named as Tunisia's new development minister.
Mr Ghannouchi has pledged that all political parties will now be allowed to operate in Tunisia.
Political prisoners would be freed and the media would be permitted "total freedom", he said on Monday.
"We have decided to free all the people imprisoned for their ideas, their beliefs or for having expressed dissenting opinions," the AFP news agency quoted him as saying.
The announcement of the new government included a pledge to abolish Tunisia's information ministry and to create a state where the media had "total freedom".
Unrest in Tunisia grew over several weeks, with widespread protests over high unemployment and high food prices pitching demonstrators against Tunisia's police and military.
