The Qualifications Authority has warned schools against automatically re-entering students in critical numeracy and literacy tests if they have failed once already.
Thousands of teenagers failed the new NCEA tests in May with Māori and Pacific students hardest hit.
About 55,000 teens attempted round of tests with pass rates of 59 percent in reading, 56 percent in writing, and 46 percent in numeracy.
Students must pass the test and tests in reading and writing before they can receive any NCEA qualifications though this year and next they can complete specific NCEA standards in order to meet the requirement.
Initial assessments of students' performance in the May tests said schools should: "Ensure students have undergone sufficient additional teaching to address areas of weakness, and that they are well prepared before they attempt the assessment again".
The May results were similar to trials of the tests in recent years, but principals are increasingly alarmed by the effect on Māori and Pacific students and warned the system needed a rethink.
An English teacher told RNZ the tests were a waste of teacher time and were causing "untold harm".
"They are appalling and the biggest turn off to education I've ever seen."
A parent told RNZ repeated failures were heartbreaking.
"Our ADHD son with learning difficulties has not passed this two times now and another attempt in a few weeks. It's a stress point for all of us. The school is doing what they can but they've said they're struggling as well. They've put extra resources in place for the kids. We are heartbroken for our son," she said.
The Qualifications Authority's interim assessment of the numeracy results said students who did not pass or who were borderline needed to take a position on questions and then justify that position by doing more than just restating their claim.
Students also had problems interpreting questions correctly, understanding problems, selecting a correct procedure and calculating or reasoning correctly.
The report said students who were clearly at or above the required standard were able to locate a position on a timeline, read line graphs and a time series graph, and interpret the scale on a map.
An assessment of performance in reading and writing said areas requiring improvement included grammar and punctuation, organising writing logically, and selecting appropriate vocabulary and sentence strucures.
The tests sat in May are available on the NZQA website, for: reading, writing and numeracy.