Less than half of Auckland secondary school students have been turning up for their NCEA exams.
The Qualifications Authority (NZQA) told RNZ that attendance at NCEA exams in the region in the first two weeks of exams averaged 48 percent.
The low attendance was due to a new rule that ensured students in Auckland, and also those in Northland and parts of Waikato, automatically received an unexpected event grade from their school for any exams they missed.
The rule recognised that teens in those areas spent more time in lockdown than students in other parts of the country.
NZQA said attendance in the first two weeks of exams was 60 percent in Northland and 70 percent in Waikato.
It said average exam attendance in the rest of the country was 82 percent.
Last year, the national average rate of attendance was 86 percent.
NZQA assessment deputy chief executive Andrea Gray said it had expected that Covid-19 would reduce exam attendance in 2021.
"The changes made to NCEA and UE [University Entrance] this year - including the unexpected event grade process for students in Northland, Auckland and parts of Waikato - are designed to ensure students would not be disadvantaged by the disruption caused by Covid-19," Gray said.
Students and principals have previously told RNZ that exam candidates were likely to skip exams where they had a good unexpected event grade, so they could concentrate on other exams where they had weaker results.
NCEA and scholarship exams finished yesterday.
NCEA results will be available on 20 January and scholarship results on 10 February.