Tertiary Education Minister Steven Joyce says he was not informed about an alleged online cheating service because an investigation failed to find sufficient evidence to proceed.
The language website Assignment 4U reportedly wrote papers for international tertiary students attending universities, polytechnics and other tertiary institutions.
A former employee of the company claimed to have written to several institutions, including the New Zealand Qualifications Authority (NZQA), warning them about the service but had no replies, Radio New Zealand reported.
Mr Joyce said an internal investigation was underway at NZQA to find out why he was not told about the allegations.
"My understanding is they investigated at the time and didn't have enough evidence to proceed further.