Tunisia has banned face-covering veils in state-run buildings for security reasons, ending a policy of official tolerance for them.

Prime minister Youssef Chahed signed an order on Friday demanding that ministers, governors and heads of public establishments "take the necessary dispositions to stop all people whose faces are covered from entering public buildings".

The measure said the ban was needed "to preserve public security" and ensure the smooth running of establishments.

The niqab that hides the face was banned in state-run spaces under former president Zine El Abidine Ben Ali, toppled in 2011.

However, it has made a gradual comeback amid heightened concern over attacks, including two last week.

A female suicide bomber, her face covered, wounded nine people, mainly police officers, in an October attack in central Tunis.

France - home to many Tunisians - was the first country to ban a full face veil in 2011 with a number of other countries following suit, including Denmark last year.