The Jewish Leadership Council has written to the equalities watchdog, the Equalities and Human Rights Commission, to express its concern at moves within the Universities and Colleges Union to reject the widely-accepted definition of antisemitism.
A motion tabled at the UCU's congress this weekend will propose that the union distances itself from a definition drawn up by the European Union.
The European Union Monitoring Centre on Racism and Xenophobia provided a working definition which guarded against racists who use anti-Zionism as a cover.
But the UCU motion argues that the definition does not allow for an open discussion of Israel. The UCU has been vocal in the boycott Israel campaign.
Senior figures in the Jewish leadership have voiced concerns to Trevor Phillips, chair of the EHRC. A letter has been sent from the Board of Deputies, the Jewish Leadership Council and the Community Security Trust, urging the body to make a stand on the issue.
The Jewish organisations have suggested that Mr Phillips re-emphasise the recommendations of the Macpherson Report into the murder of the south London teenager Stephen Lawrence.
This defined a racist incident as "any incident which is perceived to be racist by the victim or any other person", and is now the definition used by police when antisemitic attacks are reported.
The Board, the JLC and the CST have also written to UCU general secretary Sally Hunt and TUC general secretary Brendan Barber to ask them to sign up to the Macpherson definition of
Sources at the EHRC said the organisation stood full square behind the Macpherson definition of racism and believed it should apply to all ethnic communities.
In a tough statement, a spokesman for the Board, the JLC and the CST said: "After several years of promoting discriminatory boycotts and ignoring the resignation of dozens of Jewish members, UCU has never taken claims of antisemitism in the union seriously. Now, in a final insult to its Jewish members, UCU is cynically redefining the meaning of 'antisemitism' so it never has to face up to its own deep-rooted prejudices and problems.
"The joint representations by senior communal leaders to the leaders of UCU, the EHRC and the TUC send a clear signal that our community will not sit back and allow further red lines to be crossed as the boycotters unleash moves designed to curtail the rights of British Jews on our campuses."