The man enrolled as a biomedical science student in 2010. His application to medical school was later rejected, but he pretended otherwise and carried on attending lectures and tutorials and working on group assignments for two years.
He avoided detection until his name appeared on a joint assignment last week.
"His name did not appear on the class list. He was then confronted about what he was doing within the space of a few hours. He admitted that in fact he was not a medical student," Dr Bagg said.
"He doesn't give a good explanation. You need to understand that this individual is in great distress, his family are in great distress and we are quite concerned for his wellbeing."
Faculty dean Professor John Fraser said evidence was being collected about the man's activity over the past two years. Police officers yesterday issued him with a trespass order, banning him from university property.
"You must understand this person went to a considerable length to hide that he was not eligible and although we are very concerned that he was able to get away with that, I would like to tell the public that our university operates on the highest possible standards, which we intend to maintain," Professor Fraser said.
Dr Bagg said that while third-year students were all allocated to 10 half-days at a hospital, he was satisfied the man did not participate.
Auckland District Health Board chief medical officer Margaret Wilsher said the accreditation and monitoring of medical students within the hospital was the responsibility of the university.
"I have spoken with the dean and he has assured me there is no evidence the person in question has had direct contact with any of our patients or their families."
Dr Bagg said it was "extremely unlikely" the man could have carried on his ruse for much longer, as from the fourth year on students mostly participated in closely monitored clinical work.
