Tunisian Prime Minister Youssef Chahed has banned the wearing of the niqab, the full face veil, in public institutions for security reasons, an official source said on Friday.
The decision follows a suicide bombing in Tunis by a wanted militant. Witnesses said the suicide bomber, who blew himself up on Tuesday, was disguised in a niqab. The Interior Ministry denied this.
It was the third such incident within a week and came as Tunisia prepares for autumn elections and at the peak of a tourist season in which the country hopes to draw record numbers of visitors. Islamic State has claimed all three attacks.
"Chahed signed a government decree that bars any person with an undisclosed face from access to public headquarters, administrations, institutions, for security reasons," the official source told Reuters.
In 2011, women were allowed to wear the hijab and niqab in Tunisia after a decades-long ban under secular presidents Zine El Abidine Ben Ali and Habib Bourguiba, who rejected all forms of Islamic dress.
Tunisia has been battling militant groups operating in remote areas near its border with Algeria since an uprising overthrew Ben Ali in 2011.
Tunisia is one of the few countries in the region where Islamists share rule with secular parties.