A heated debate over religious symbols and public security has broken out in Italy after a Muslim woman tourist wearing a niqab which left only her eyes visible was refused entry to a museum in Venice.

The woman, accompanied by her husband and daughter, had bought a ticket for Ca Rezzonico, the Grand Canal palace which houses exhibits on eighteenth century Venice. When she tried to enter the museum however she was barred by a guard "for security reasons".

Filippo Pedrocco, director of Ca Rezzonico, said he had apologised to the woman, whose nationality was not disclosed. He said Italian law forbade the wearing of face-covering masks or hoods in public because of the terrorist threat.

In adition there were local rules requiring wearers of masks during the Venice Carnival to remove them so their identities could be established. However the guard had made a "serious error" in interpreting the regulations, which had to be applied with "common sense".

Massimo Cacciari, the centre Left mayor of Venice, said visitors to Venice museums could "wear what they liked", provided their eyes were visible. He said the guard had been "a bit stupid" but would not be sacked.

However Carlo Giovanardi, a spokesman for the centre Right government of Silvio Berlusconi, said Muslims living in Italy realised they had to adapt to Western rules of behaviour, and many Muslim residents had said they supported the guard's action.

Giancarlo Galan, president of the Veneto region, said "We must respect the customs and styles of dress of others - but in return they must respect our laws". He added that guards at the Topkapi Museum in Istanbul would rightly refuse entry to visitors who were "scantily" dressed and so offended local sensibilities.

The Venice guard was also defended by Alberto Mazzonetto, head of the right wing Northern League faction on the Venice council, who said that in his view all Muslim women should be "checked" in the streets and squares of Venice.

Gianni Curti, head of the security firm which employs the 27-year-old guard, Diego Lupo, said he had merely "scrupulously observed the regulations." He said in future all Venice museums would set aside a private room in which the identity of veiled Muslim women could be checked by a female guard.

Luigo Bobba, a left-wing Catholic parlamentary deputy in Rome, said the guard had been right to refuse entry to the woman, "just as he would have barred someone wearing a Balaclava helmet. It is not a question of religious freedom but of security. If a woman wears a chador, or headscarf, you may like it or not like it, but you have to respect the woman's right to wear it. However if a woman covers her face in a public place, that is a different matter".

Mr Lupo, who has worked a museum guard for five years, told Corriere della Sera he was "not a racist" but had only "done his duty". "I would have done the same if the woman had been Italian".

Emma Bonino, the former European Commissioner and a leading Italian liberal and feminist, said it was "not a question of religion but of public order. It is a fundamental principle of our society that individuals are responsible for their public acts and must be recognisable". She said it was "not a question of tolerance or intolerance. It is a question of the law and the rules".