Italy on Wednesday began its appeal against a European Court of Human Rights ruling condemning the display of crucifixes in Italian schools in a case that could affect all of Europe.

The court's ruling in November found the display of crucifixes in Italian schools breached the rights of non-Catholic families, drawing howls of anger from Church and political leaders in the staunchly Roman Catholic country.

Italy's education minister attacked the initial ruling that crucifixes "restrict the right of parents to educate their children in conformity with their convictions," insisting the crucifix was a "symbol of our tradition."

Italian mother Soile Lautsi, whose two children attended a state school near Venice, took her case to the European court after a long battle pitting her against Italy's Catholic establishment.

Catholicism was the state religion in Italy until 1984, and a 1920s ruling ordering the presence of crucifixes in schools was never abolished.

The court's final ruling could be applicable to schools in all the Council of Europe's 47 member states.

Lautsi first brought the case eight years ago when her children, Dataico and Sami Albertin, aged 11 and 13, went to the state school in the northern Italian town of Abano Terme.

She was unhappy crucifixes were present in every classroom and complained to the school.

After education chiefs refused to remove the crosses, she spent several years fighting the decision through the Italian courts before taking the case to the Strasbourg court.

A dozen other countries, including Armenia, Bulgaria, Cyprus, Greece, Lithuania, Malta and Russia, are so-called third parties in the case and can present written observations.

Their lawyer, American law professor Joseph Weiler, warned against "an Americanization of Europe with a single rule that goes against the multiplicity of constitutions."

"Countries also have the right to define themselves in relation to their religious heritage," he said, noting that Christian crosses feature on national flags and money.

"All children in Europe, atheist or believers, learn that the right to believe and the right not to believe are realities," he said, pointing out that not all Britons who say "God save the queen" are believers.

Lautsi's lawyer, Nicola Paoletti, stressed that her client was "secular" and not "atheist."

"She has never said anything against the Catholic religion, she wants her two children to be educated according to the principle of secularism," Paoletti said.

"And yet, children in public schools think that the state identifies with this religion, and if they're not Catholic, then they can feel a minority and suffer as a result," he said.

The Italian government's lawyer, Nicola Lettieri, described the crucifix as "a passive symbol with no relation to teaching, which is secular."

"Where is the indoctrination, we're not distancing children from their parents' convictions," he said, adding that "the crucifix may be the expression of a Christian tradition, (but) Italy does not proselytize.