National is urging Education Minister Chris Hipkins to meet with school principals upset with the way the NCEA review is going.
Nearly 40 principals put their names to an open letter published in newspapers on Sunday, saying the process has been rushed and they haven't been asked for their thoughts.
"We agree a review of NCEA is necessary because the framework can be improved to better prepare our young people for the challenges ahead," it reads. "However, the review is flawed and we will not stand idle on the sidelines watching a fraught process pass us by."
National leader Simon Bridges says principals' expertise matters.
"They're at the coalface so they know our education system and they know what's good for our children and young people far better than Mr Hipkins and his colleagues, and the Government needs to recognise that," he said on Sunday morning.
"This Government continues to show if you're not on one of its 130 working groups or you disagree with its bad ideas then it's not willing to listen."
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Baradene College's Sandy Basley said students are being used as guinea pigs.
"I think we've got to be making sure we're not going to be doing something that is going to be a few years down the track."
National's education spokeswoman Nikki Kaye has written a letter to Mr Hipkins, telling him he needs "direct engagement" with principals.