The University of Birmingham union has refused to explain what disciplinary action it has taken against its Friends of Palestine Society after it hosted a US army veteran who compared Gaza to a concentration camp.
During a lecture last month Mike Pryser said: "I think you can very much draw an equal sign between what the Nazis did to the Jews and what is done to the people of Palestine."
At the end of a two-week investigation, the student union, the Guild, confirmed sanctions were imposed, but would not give details.
But a post on the PalSoc website claimed that the union had taken no action against it and had found it to have followed correct procedures.
The Board of Deputies and Union of Jewish Students plan to take up the matter. Eytan Halon, campaigns officer of Birmingham JSoc, said: "The Guild has put into place policies to identify racism on campus. Despite this, we are now aware that the comments that clearly match the Guild's definition of antisemitism, and which were later endorsed by PalSoc, have gone completely unpunished.
"As far as we're concerned, this matter is not yet concluded."