A Jewish leader drew the wrath of gay rights' groups on Monday by saying that the legal recognition of homosexual couples was "unacceptable".
Riccardo Di Segni, Rome's chief rabbi, urged the Jewish community to speak out against government plans to give certain rights to cohabiting heterosexual and same-sex couples under a bill known as DICO.
The bill, which has yet to win parliamentary approval, has come under repeated attack from the Catholic Church, which has expressed particular alarm over its extension to gay partners.
In a long article to be published later this week in the Jewish monthly Shalom, Di Segni rebuked the Italian Jewish leaders for their "strange silence on this hotly debated issue".
He noted that this silence was in strong contrast to the Catholic Church's active condemnation of the DICO bill and said there were "good reasons to break it".
"Society is about to make a decision which, according to our traditions, abundantly exceeds permitted limits and it is our duty to oppose these decisions and not remain indifferent," Di Segni said.
Left-wing MP and veteran gay rights' campaigner Franco Grillini immediately accused the rabbi of "unacceptable anti-homosexual racism".
"Perhaps he's forgotten that along with the Jews, there were many gays in the Nazi death camps," added Grillini, who is honorary chairman of top Italian gay rights' association Arcigay.
Arcigay, meanwhile, accused religious leaders of creating a "homophobic Holy Alliance".
It said Di Segni and Catholic leaders were turning an upcoming pro-family values rally into an anti-gay demo.
The 'Family Day' demo, which has been promoted by Catholic groups and is backed by the centre-right opposition, is to be held in Rome on Saturday.
Supporters of the protest are calling on the government to do more to help families and, although the DICO law is not mentioned in their manifesto, they oppose putting marriage on a par with "other forms of cohabitation".
Italy is one of the few countries in the European Union which does not recognise unwed couples or same-sex unions.
Centre-left Premier Romano Prodi promised such a law in his election programme.
Under the terms of the DICO bill, cohabiting couples would be able to register their union, obtaining certain financial and inheritance rights and 'next of kin' rights if their loved one is physically or mentally incapacitated or in hospital.
Prodi needs the full support of his disparate, nine-party coalition if the DICO bill is to pass the Senate without opposition help.
The premier holds only two more Senate seats than the Silvio Berlusconi-led opposition and DICO supporters fear the bill could be sunk there by rebel Catholic allies.
Justice Minister Clemente Mastella, who heads the tiny, Catholic UDEUR party, is one of the bill's most vocal critics.
The minister will be attending Saturday's Family Day rally.
