An angry row over the recognition of conversions to Judaism has erupted once again between the Orthodox rabbinical establishments of Israel and the US.

The dispute arose following the Israeli Chief Rabbinate's refusal to authorise at least two conversions performed by rabbis affiliated to the Rabbinical Council of America (RCA).

The decision by the Israeli rabbis prompted the RCA to label their conduct a "disgrace".

The giyurim - or conversions - were authorised by Rabbi Gedalia Dov Schwartz, who heads the Beth Din of America. Although his conversions have been recognised by the Israeli rabbinate in the past, this time they were deemed to have been performed by "a third party" and, as such, were declared invalid.

Although the Israeli Chief Rabbinate's jurisdiction is limited to Israel, its rulings are important for Orthodox communities around the world because only the conversions it recognises are valid for those who wish to get married as Jews in Israel.

It is also much more difficult for converts to receive Israeli citizenship without a rabbinate-recognised conversion.

In the past, the Israeli rabbinate has tried to enforce its own stringent, strictly-Orthodox standards of conversion on rabbis and Batei Din (rabbinical courts) around the world by only approving conversions performed by rabbis they had approved of in advance.

This has already led to arguments with the RCA. However, Rabbi Schwartz's conversions and rulings had in the past been recognised by the Israeli rabbis.

RCA president Rabbi Shalom Baum said they were investigating "this latest disgrace and we demand a thorough report of how this could happen."

The Chief Rabbinate in Jerusalem responded that every request for recognition of conversion it receives "is examined on its own merits. There are no total authorisations, or non-authorisations, for any rabbi".

In response to outcry from the RCA, however, the Ashkenazi Chief Rabbi later clarified that he had urged the official in charge of the Conversion Department to authorise the conversion papers.

But it was not clear whether this will be sufficient for the converts to be recognised as Jewish, should they choose to live and get married in Israel.