Prime Minister Youssef Chahed decided Friday to ban the niqab Muslim face covering for women in Tunisian government offices "for security reasons", his office said.
It said Chahed signed a government circular "banning access to public administrations and institutions to anyone with their face covered... for security reasons".
The ban on the niqab, which covers the entire face apart from the eyes, comes at a time of heightened security following a June 27 double suicide bombing in Tunis that left two dead and seven wounded.
The interior minister instructed police in February 2014 to step up supervision of the wearing of the niqab as part of anti-terrorism measures, to prevent its use as disguise or to escape justice.
The niqab and other outward shows of Islamic devotion were not tolerated under the regime of longtime autocrat Zine El Abidine Ben Ali but have made a comeback since he was toppled in Tunisia's 2011 revolution.
A number of countries have imposed ban against the wearing of niqab in public.
France outlawed citizens wearing any form of face covering in public in 2010, effectively banning the niqab.