* Priority is security plus political and economic reform -PM
* Ben Ali's RCD party keeps significant presence in cabinet
(Adds central bank, background)
TUNIS, Jan 17 Tunisia's ministers of defence, the interior, finance and foreign affairs will keep their posts in the new government but opposition leaders including Najib Chebbi will also have posts, the prime minister said on Monday.
The government hopes the new coalition cabinet will help to stabilise the north African country of 10 million, still in turmoil after the sudden collapse of former president Zine al-Abidine Ben Ali's rule last week during a popular uprising.
"We are committed to intensifying our efforts to reestablish calm and peace in the hearts of all Tunisians. Our priority is security, as well as political and economic reform," Prime Minister Mohamed Ghannouchi told a news conference.
He named Chebbi, founder of the opposition PDP party, as minister of regional development.
Ahmed Ibrahim, leader of the Ettajdid party, was named minister of higher education and Mustafa Ben Jaafar, head of the Union of Freedom and Labour, got the health portfolio. Ghannouchi also named a new governor of Tunisia's central bank, Mustafa Kamel Nabli.
Tunisian security forces used tear gas and water cannon to disperse a protest of up to 1,000 people in central Tunis earlier on Monday demanding that the ruling party give up power.
Their slogans included "Out with the party of the dictatorship!" and "Out with the RCD!" -- the party of Ben Ali, who fled to Saudi Arabia on Friday. It still has a significant presence in the cabinet of Ghannouchi, who himself is an RCD member.
Interior Minister Ahmed Friaa was originally appointed only last week in Ben Ali's final days when the then president tried to mollify a protest movement against poverty, corruption and political repression. (Reporting by Tarek Amara, writing by Andrew Hammond, editing by David Stamp)