NZQA has identified an error in the design of an NCEA Level 2 maths question, but says that wouldn't have prevented students from attempting it.
NZQA deputy chief executive of the assessment division, Kristine Kilkelly, said the error was found in the Algebra paper (standard 91261).
"To identify the error, students would have had to complete workings which markers will be able to consider.
"Those workings will have demonstrated Excellence [grade] to the markers, so we do not expect any students will be disadvantaged."
She said there were also procedures in place for markers to address the problem and ensure students were not at a disadvantage.
"NZQA will review its quality assurance procedures to find any improvements for this kind of question."
However, some high school students have taken to social media saying the NCEA Level 2 maths exam was far too hard.
One student, Oliver Wright, said many did not expect to pass.
"I walked out after an hour and a half, and then when I walked out all my mates walked out and heard several walking out at that time as well... It was just a weird vibe, like everyone thought it was hard," he said.
It's not the first time an NCEA maths exam has faced complaints and problems. Last year, a review panel found an impossible-to-answer question in a 2016 Level 3 statistics exam was a late addition that was not checked independently.
In 2016, year 11 students and teachers also complained that an algebra NCEA Level 1 exam was too difficult.