Israel’s Ashkenazi Chief Rabbi David Lau has admitted that some immigrants from the former Soviet Union have been sent for Jewish DNA testing as a condition of receiving a marriage licence.

The admission has embarrassed Interior Minister Aryeh Deri, who denied such testing is conducted, and angered Avigdor Lieberman, whose Yisrael Beitenu party relies on the Russian-speaking immigrant vote.

Mr Lieberman demanded that both the Ashkenazi and Sephardi Chief Rabbis resign.

“DNA testing is outrageous discrimination and racism by the Strictly Orthodox establishment,” he said. “The Chief Rabbinate must decide if it is a state institution or the inquisition.”

In justifying the action, Rabbi Lau said that the need for DNA testing stems from the contradiction between halachah, which requires a person’s mother to be Jewish, and Israel’s Law of Return, which grants citizenship to anybody with one Jewish grandparent regardless of whether it is on the father or mother’s side.

Rabbi Lau said: “The onus is on a person wanting to claim that they are [halachically] Jewish to prove it to the rabbinical court and in every case the rabbinical courts strive to work with sensitivity to help and to make things easier in the Judaism clarification process.”

“In some isolated instances it has happened that somebody insists that he knows that he is Jewish but does not have the documents available that confirm what he says, or a contradiction is found in what he is saying. In such cases, in order to help the person, the court proposes that the claimant undergo a DNA test to strengthen his claim.”

Rabbi Lau added that because DNA testing is not officially recognized as proof of Judaism by the Orthodox establishment it “does not fully clarify if a person is Jewish according to halacha, but helps in the enquiries.”

He insisted nobody is forced into undertaking the tests.

But Rabbi Seth Farber, director of Itim, an body that helps Israelis to navigate the rabbinical bureaucracy and which has documented 20 recent cases of Israelis being sent for such DNA testing, said that because the Orthodox rabbinate has a monopoly on Jewish marriage in Israel, the DNA test demand is in practice a form of coercion.

In the cases documented by Itim, many of those applying for marriage licenses were also required to bring DNA tests from their mothers. The entire process was described as “arduous, awkward, inconvenient and sometimes humiliating.”