Police and the Qualifications Authority are investigating claims a commercial cheating service for tertiary students is operating in Auckland.
A former employee of the language website Assigment4U says it provides a service to overseas students, particularly Chinese, offering university essays for a fee.
The website says it provides counselling services to significantly improve the academic achievement of clients.
The former employee says he worked for the company in 2007, writing essays that were then bought by international students.
Minister for Tertiary Education, Skills and Employment Steven Joyce says the claims are a concern and the Qualifications Authority, which was tipped off about the service three months ago, should have told him sooner.
He says he spoke to the authority's chief executive on Saturday and indicated he was concerned not to have been advised earlier.
Mr Joyce says international education is an important industry for New Zealand and he would have expected a "heads up" much sooner.
Auckland University Vice Chancellor Stuart McCutcheon says the claims are speculation at the moment, however, if they proved to be true, the university would be worried.
He says students are expected only to provide original work in their assignments, but the university has no evidence at all that there is a substantial use of this type of service by its students.
Professor McCutcheon says most students have to sit a final exam which makes up a large part of their final grade so it would be difficult for them to gain qualification using such a service.