The London School of Economics is investigating claims a Jewish student was assaulted on a trip where a Nazi-themed drinking game was being played.
The student suffered a broken nose after objecting to the game but does not wish to press charges, according to the university's students' union.
It took place on a French skiing trip organised by the athletics union in December, it is claimed.
The university said it was "prepared to take disciplinary action".
The game involved arranging cards in the shape of a swastika and requiring players to "salute the Fuhrer", according to the students' union.
A Jewish student, who has not been named by the university, is said to have objected to the game and was later assaulted.
He reported what happened to the LSE Students' Union's Jewish Society, but according to the society, does not wish to report the incident to the police.
The society's president, Jay Stoll, said the attack did not represent the experience that the majority of Jewish students had at the university.
He said there was "absolutely no excuse" for the collective attack on a community.
Speaking to BBC London, Alex Peters-Day, general secretary of the LSE Students' Union, said she "absolutely rejected" the suggestion that there was an anti-semitic ethos at the university.
She said it was an "incredibly small minority" of people who had taken part in the game and anti-Semitism was in "no way endemic".
A spokesman for the university, said: "Students must abide by clear standards of behaviour set by both the LSE and the Students' Union and breaches of those standards are taken very seriously.
"We do not tolerate anti-Semitism or any other form of racism."
Last year, the university was criticised over its decision to accept £300,000 for research from a foundation run by the son of Libyan leader Col Muammar Gaddafi.
LSE director Sir Howard Davies resigned over the controversy.