A recent gay pride parade in Jerusalem provoked an angry reaction from Ultra-Orthodox Jews.
The Israeli supreme court has ordered the government to recognise same-sex marriages performed abroad.
Five couples who had obtained common-law same-sex marriages in Canada and wanted to appear as married couples on the country's population registry had petitioned the court with the support of an Israeli civil rights group.
Six of the seven judges voted for the move while the lone dissenter was an observant Jew, highlighting the controversy the decision arouses among Israeli religious groups.
Moshe Gafni, an ultra-Orthodox legislator, said:"We don't have a Jewish state here. We have Sodom and Gomorrah here."
He told Israel's Army Radio: "I assume that every sane person in the state of Israel, possibly the entire Jewish world, is shocked, because the significance is ... the destruction of the family unit in the state of Israel."
Gafni said he would consider presenting a bill to parliament that would bypass Tuesday's Supreme Court ruling and make recognition of all same-sex marriages illegal...
RELATED: Israel's High Court has ruled that same-sex couples married in countries where gay marriage is legal can be registered as married couples in Israel: