However, Otago University academic and international pro-vice-chancellor Prof Vernon Squire said the university was aware of sites where its students could buy and sell old essay and exam answers and examples of assignments for "reference" purposes.
Some students had been caught and disciplined for passing off, as their own, work bought online.
Prof Squire warned students of the dangers of using such sites - even if just to help with study or exam preparation.
"There are no guarantees as to the quality or currency of any material they might purchase or access. Moreover, users of such sites, both the suppliers and the users, may be in danger of breaching copyright law and could face the risk of action by the copyright holders of the material being procured."
Prof Squire warned people thinking about using such websites to cheat that the university had "strong policies" in place to deal with plagiarism.
"As well as automated plagiarism monitoring, any irregularities in regard to the performance of an individual student would be detected by lecturers or tutors and would be the subject of further scrutiny," he said.
A disciplinary report released by the university earlier this year showed 45 students were dealt with for cheating and other dishonest practices last year.