From TFA linked to:
In a statement, Jann Marshall, NZQA deputy chief executive, assessment, defended the exams, saying, “Exam papers are developed and quality assured by writing teams that include experienced subject teachers at that NCEA Level.
I suppose having a dry-run with actual students to get feedback never entered anyone's mind?
That was one thing our (outstanding) physics teacher used to do, when he set an exam he'd actually sit down and try and do it in the assigned time to make sure it was feasible. He didn't have the resources of the NZQA at his disposal but he at least made an attempt to beta-test it.