It is alleged an onlooker who was helping at the event made a complaint to senior OUCA members that Macpherson and Gottardello had been "groping and harassing" female attendees during the evening.
The association has suspended Macpherson from attending further OUCA events until the end of term.
The Mirror yesterday revealed how following the Port & Policy evening on January 28, 11 OUCA council members were so concerned about the behaviour of some guests, a joint statement was produced detailing concerns.
An OUCA insider said: "This has been the talk of the university campus and heaps major embarrassment on all involved.
A spokesman for OUCA said: "The Association takes very seriously indeed all allegations of misconduct at its events.
OUCA could now face an investigation by university chiefs and one member has been suspended.
OUCA President Timothy Doyle said last night: "The association takes very seriously indeed all allegations of misconduct at its events.
Theresa May and husband Phillip were former members of OUCA when both at Oxford in the late 70s.