A students' union is investigating after a freshers' event was advertised with a poster containing an explicit reference to rape.
Cardiff Metropolitan University said the union was "appalled" and was trying to find out how the artwork was published.
It apologised for the "oversight and offence caused".
Eluned Parrott AM called the incident "deplorable" and said universities had a "duty of care" to students.
The poster, which was advertising an event when students start at the university in September, showed the back of somebody wearing a t-shirt with a comment about rape scrawled across it in pen.
It has since been taken down.
But Ms Parrott, who represents South Wales Central, said the image should never have been used in the first place.
"Rape is a serious and abhorrent crime and I find it disturbing that someone should use an image where they make light of a sexual attack to advertise a student night out," she said.
"All universities have a duty of care to ensure the safety of vulnerable young women who leave home for the first time.
"I urge Cardiff Metropolitan University to investigate how this was allowed to happen and look into ways of ensuring that something like this never happens again."
The university said: "Cardiff Met Students' Union is understandably appalled by this promotion and has launched a full investigation into how the artwork passed through our usually stringent approval procedures.
"The event is promoted by Climax Promotions and advertised by the university's Students' Union, which offers its sincere apologies for this oversight and all offence caused."