An investigation by the University of Auckland has found a man who posed as a medical student for two years went to considerable lengths to avoid being caught out.
The student attended classes and took part in a number of school activities, including the study of human cadavers, in the 2011/12 academic years, despite failing to gain medical school entry in 2010.
AAP reports he was found out only when he had to provide his student ID number for a lab assignment.
A report by the university, released on Monday, said the student's "extremely unusual behaviour" started after he attended social events and some classes in early 2011.
"He gave every impression to other students in the classes that he had been offered a place in the programme."
The student did not have a swipe card for access to many teaching areas and appeared to have tailgated other students to get in.
He also admitted waiting outside exam rooms to give the impression he was sitting exams, but would slip away when everyone went in.
"His deception was very effective since even those closest to him in the class were unaware that he was not an enrolled medical student," the report said.
The university said there is no evidence he had any one-on-one contact with patients. It decided not to complain to police because while his deception was unethical, it wasn't likely criminal and he had already suffered the consequences.
Police had already issued him with a two-year trespass notice.
AAP reports the university has also made changes, including to its student ID card system and name badges, to help prevent a repeat, although access to lectures will remain open.
The changes will also see a new automated system do remote checks on the police database - with appropriate privacy provisions - to allow the university to check if those enrolling have committed criminal offences.