Even secondary principals are shocked by the severity of a maths exam.

Some students have been left in tears after a year 11 NCEA level one maths exam - with many teachers and students alike calling it unfairly difficult.

Secondary Principals' Association President Sandy Pasley said the exam had new components which required students to do investigative work, rather than straight skills.

She told Mike Hosking it gave students quite a shock, "because it was quite different from the previous year's papers, and students really look to previous papers, as do teachers, for a guide as to what it will be like."

Sandy Pasley said NZQA will review the exams and benchmark it to determine if adjustments need to be made.