NCEA exam results published online included aggregate marks for nearly 1100 students whose online English exam was marred by a technical failure last year.
The level 1 students lost their connection to the exam server for a short period and today received derived grades based on school work completed earlier in the year.
Qualifications Authority deputy chief executive of assessment Kristine Kilkelly says 3000 students sat the exam and it was not yet clear how many were affected by the problem.
She says six of the students lost some of their work because of the problem.
Kristine says derived grades were applied in cases where students' performance might have been impaired.
"The use of the derived grade process is to really ensure that students are not disadvantaged.
"If there's any likelihood that a student could have felt that it could have affected their performance, then we do want to make sure that they are given the best possible outcome."
She says the authority had identified the cause of the problem that affected the online exam and would make sure it did not happen again.
Secondary Principals Association New Zealand president Michael Williams says the problem was unlikely to deter schools from entering students in online exams in the future.
"For those of us who've been involved in the trials for quite a long time, it's part of the learning process as we step up each year with more and more students doing it.
"We're really pushing systems to see where these faults are."
Michael says it helped that the exam affected by the problem was a Level 1 exam and not a Level 3 exam, which was more important to the students sitting it.
Meanwhile, Kristine says the authority could not see any impact on students' results from the use of the word "trivial" in a Level 3 history exam.
Some students had complained that they did not understand the word, or the manner in which it was used in a question in the paper.
However, Kristine says the pattern of results for the exam was similar to previous years and markers observed that the question was a good one.