The Post Primary Teachers' Association has released a report warning politicians to back off when it comes to making decisions about the NCEA programme.
The report, called The NCEA: can it be saved? looks at what the PPTA says are problems within the qualification caused by political meddling.
Association president Angela Roberts said the government's target of 85 percent of students achieving NCEA Level 2 put teachers under pressure to get students as many credits as possible, often at the cost of the quality of the learning programme.
"The message is very clear, it's about passing, it's about 85 percent getting level 2, it's not about kids focusing on getting the skills and knowledge they need."
She said unnecessary moderation demands also led to excessive paperwork for teachers, taking their time away from their students.
The NCEA qualification was not as good as it could be, she said.
"The qualification's become a servant to too many masters. The universities are very narrow in what they believe academic success looks like and the excessive moderation of what we do really inhibits our ability to make the most of this qualification," she said.
"If the government fails to act on the recommendations in this paper, we will see further erosion in public and teacher acceptance of NCEA."
The report will be presented at the association's annual conference late next month.