The University of Sydney has cleared a prominent academic of anti-Semitism but still threatened him with the sack in relation to an ugly protest at its main campus, in which screaming students were dragged along the ground by security guards.

University staff accused vice-chancellor Michael Spence of aiding a "witch hunt" against Associate Professor Jake Lynch, who was accused of anti-Semitic behaviour for waving money in the face of a Jewish woman, after she allegedly kicked him in the groin.

A screen grab from a YouTube video of the protest at the University of Sydney.

Professor Lynch, a proponent of the Boycott, Divestment and Sanctions campaign against Israel, was advised by the university this month that it was not satisfied his conduct "constituted anti-Semitic behaviour or unlawful harassment on the grounds of an individual's religious belief (or perceived religious belief)".