Government offices in the European Union can ban employees wearing religious symbols such as Islamic headscarves, even when they do not have contact with the public, the Court of Justice of the EU ruled Tuesday.

Such a rule can be imposed "in order to put in place an entirely neutral administrative environment," the court said.

The judgement derived from a case lodged by a worker in a Belgian local government office who challenged a ban on her wearing an Islamic headscarf, feeling that it infringed on her freedom of religion and she was being discriminated against.

The Luxembourg-based court said a prohibition "of any sign revealing philosophical or religious beliefs… is not discriminatory if it is applied in a general and indiscriminate manner to all of that administrationa's staff and is limited to what is strictly necessary."

The ruling — valid for public sector offices across the EU — backs up previous EU court judgments that found such bans can be legal in private sector workplaces.

It said national courts should decide the applicability of such prohibitions, and that public offices could also have policies limiting such bans to public-facing workers, or decide to authorize the wearing of visible religious or philosophical signs of belief.

"Each Member State, and any infra-State body within the framework of its competences, has a margin of discretion in designing the neutrality of the public service which it intends to promote in the workplace, depending on its own context," it said.

"However, that objective must be pursued in a consistent and systematic manner, and the measures adopted to achieve it must be limited to what is strictly necessary."