Year 10 students have been trialling new high-stakes literacy and numeracy tests in schools this week.
From 2024 teenagers must pass the online assessments to get any level of the NCEA school qualification.
James Cook High School principal Grant McMillan said he hoped the Qualifications Authority would change the tests because initial feedback indicated they were too difficult.
"If what we have in front of us right now is what is actually introduced in the future, they will be too hard both in terms of the design of the assessment, the level some of it is pitched at, the fact that you need to spend so much time in words when you're supposed to be working in mathematics, and some of the mechanical aspects," he said.
"The literacy, which is reading and then writing online, tries to jam a lot of content into a smallish time space and parts of it appear to be at a higher level than what the curriculum currently expects."
McMillan said he was pleased the government had decided to postpone the tests' introduction to 2024, but he was disappointed they would be available only twice a year rather than when students were ready to do them.
Onehunga High School principal Deidre Shea said students had so far done the reading and numeracy tests and most believed they would have passed.
"The reading students coped well and came out feeling they had acquitted themselves well. With the numeracy, we've just done that this morning, and many of the students ran out of time so that might be one to look at in terms of the amount of material within the timeframe that was expected to be answered," she said.
Freyberg High School principal Peter Brooks said his school also trialled the tests this week but he was no fan of the new assessments.
"They've gone back to the ark with these one-off tests, which is just ridiculous. I don't know where this idea came from that you could test for literacy and numeracy on one day, online, just on computers. It's just fraught with problems. To me, it's a giant leap backwards in terms of determining whether the kid's literate or numerate or not."
Brooks said he had been told students would get two opportunities a year to sit the tests but he expected some would fail multiple times and the system would disadvantage new migrants and vulnerable students.
"For 75 per cent of students they are just going to get literacy and numeracy in Year 10 and carry on with everything else. So you're talking about the vulnerable and the ones who need it, like migrant students, ones from overseas, students who for various reasons have been held back and what is it doing to one of those students who have failed four times and then be waiting until level 2 to sit it again," he said.
The Qualifications Authority said the assessments were being rigorously checked to ensure they were at the right level.
It said it would extensively evaluate all aspects of the pilots, including feedback from participants and whether the standards and assessments were at the right level.
"As we are still working through the first assessment week, it is too early to respond to feedback about the assessment activities. However, we have received a number of positive comments from pilot schools over the last three days, and there is no time limit on the assessment activities - schools are advised that each activity is designed to be completed within 60 minutes by most students who are ready to undertake the assessment, but students should be given more time if they need it," it said.