JERUSALEM (AFP) - Non-Jewish spouses of Israeli homosexuals can now obtain citizenship under an interior ministry decision applicable since Tuesday.

"The same-sex partner of a person eligible for the law of return, and who does not live in Israel, may also become Israeli," a ministry statement said, adding that the ruling applies only to married same-sex couples.

Under the law of return, any Jew has the right to ask for, and to be granted, Israeli citizenship.

That right also extends to the partner of the applicant, but had previously been granted only to heterosexual couples.

"Israel's doors are now open to any Jew and his family, without discrimination based on lifestyle," Interior Minister Gideon Saar said in a statement.

The Jewish state is considered a trailblazer in the promotion of and respect for gay rights, especially in terms of adoption for same-sex couples.

However, civil marriage does not exist in Israel, where the solemnisation of marriage is entirely controlled by the state rabbinate, and homosexual unions are not in themselves recognised.

Ultra-orthodox parties see the new move as an attempt to undermine the authority in civil matters granted to them since the creation of the state of Israel in 1948.

"The interior ministry decision is atrocious, outrageous and anti-Jewish, yet another step in the campaign being waged in Israel against religion," Shas party MP Nissim Zeev said in a statement.

For Mr Zeev, the ruling equates to "the dangerous institutionalisation of the phenomenon of homosexual families in Israel".