Massey University could scale up as many as 1000 students' grades after a lecturer handed out some exam questions before the exam was sat.
Massey University is investigating the Albany-based lecturer after the exam questions ended up on a Chinese language website and were seen by students at all three Masseycampuses.
Assistant vice-chancellor Luanna Meyer said students who took the first-year fundamentals of finance paper would get "the benefit of the doubt".
"Students just beneath a grade cut-off will be given the next grade," she said.
Students from all three campuses could take up the matter with department staff if they still felt hard done by, she said.
"If students feel disadvantaged, they will also have recourse to pursue that [option].
"We have absolutely no way of knowing which students might have picked up these questions and gone to the book, found the answers and memorised them."
Professor Meyer strenuously denied that the incident would tarnish Massey's image.
"Why would it affect Massey's image? We have thousands of examinations with thousands of students. We couldn't have more rigorous procedures for ... such a large university."
Massey was speaking with the lecturer and would issue guidelines to prevent any such incident from recurring. But the institution would continue to trust its staff, she said.
"We trust the academic expertise of our staff. Occasionally, a person makes a mistake, but we do not police our staff."
Professor Meyer said Massey could not guarantee equality across the three campuses. The best it could hope for was equivalency.
"It can never be equal. We mean for it to be equivalent."
She said Massey would release the findings of the investigation in the next few weeks after the lecturer had been given the chance to respond to the allegations.
