Students who sat a digital version of NCEA Level 1 English last week have been offered a derived grade following technical problems with the exam pilot.
Some students encountered problems logging into the exam last Thursday morning, the Herald reported last week.
The digital exam was a pilot version of the traditional paper test, and part of the New Zealand Qualifications Authority's plans to have the majority of exams online by 2020.
Students log onto a NZQA website, where they find a digital version of the exam paper and answer the questions online.
Last Thursday, Zoe Tinkler, 16, a Year 11 Diocesan School for Girls student, spoke to the Herald about "teething problems" which hindered some students at the beginning of the test.
One mother reported her son sat the exam in Christchurch where his school computer "froze several times and crashed twice during the exam".
"The teachers and examiners took half an hour to fix it," she said.
At the time, the NZQA said it was aware of the problems and was looking into it.
The Herald can now reveal the exam body later sent a letter to all schools affected, apologising for the "technical issue that affected some students".
"NZQA apologises that the pilot did not work as expected in these instances," the letter, signed by deputy chief executive digital assessment transformation, Andrea Gray, said.
Student experience of the digital exam varied, she said.
"While it was very positive for some, others moved to answering the examination using the back-up scripts provided."
NZQA's first priority was the students, she said, adding she wanted to "ensure no student who was affected is disadvantaged".
"We will work with you to ensure this is the case. This includes the bulk derived grade process and that where students swapped between the online and the paper exams, NZQA will bring the two together for marking."
An investigation had begun to find out what happened, she said.
"Unfortunately, extensive prior testing did not reveal the issue experienced today [Thursday].
An NZQA spokeswoman told the Herald just under 1800 students from 37 schools were affected.
Tinkler told the Herald today her classmates were feeling relieved since they received the letter.
"Everyone that experienced issues is feeling relieved, especially because we are all encouraged to prepare well for our school mock examinations which is taken as our derived grade," she said.
"Those who did encounter issues are reassured that the grade they will be awarded is an accurate representation of their effort and ability."
NZQA is piloting four NCEA Level 1 exams in digital format this year, including English, classical studies and media studies.
More than 100 schools, and 14,000 pupils are registered to take part in the trials and pilot exams this year, according to the NZQA website.