Principals say some under-pressure teachers are essentially teaching to scripts as they get to grips with new primary school maths and English curriculums.
Some say it's fine as teachers learn to teach new content, but they warn the practice should not stick because it will bore children and lead to lower achievement.
The government is pushing for more structured teaching with careful step-by-step instruction to ensure all students learn the same content in a clear sequence.
It says there is no requirement to use scripts and it doesn't produce any.
However, teacher educators warned this week that the government's curriculum changes were similar to the UK and parts of Australia where highly-scripted lessons were common.
Principals told RNZ some teachers were using new maths resources as the basis for teaching the new curriculum introduced this year and some programmes for teaching children to read and write required close adherence to a scripted method of teaching.
One principal told RNZ they deliberately did not order the government-funded maths resources because they didn't believe they were very good and feared teachers would teach directly from them rather than developing their own lessons.
But others said an initial reliance on slides and scripts was not a bad thing.
They said pupils sometimes learned new information better if part of a lesson was regular and predictable.
Dunedin's George Street Normal School has embraced structured teaching.
Its principal, Robyn Wood, said teachers used slides when they started with the new maths curriculum, and elements of the school's structured literacy approach for reading and writing were scripted.
"We did start off with slides and all of that and I believe that was necessary to get the consistency and the knowledge of what we needed to include. That was a big pedagogical shift for us and we needed to have that as a scaffold for our teachers," she said.
Wood said some structured literacy programmes had scripted elements, but her school was "now well, well away from that".
"Sticking to a script, you're kind of stuck there whereas once you know what you're doing and you're really confident in what you are required to teach and how it aligns with the curriculum you are much more easily able to pivot to the needs of the children in front of you," she said.
A literacy expert working with schools, Carla McNeil, said structured lesson guides or scripts were a scaffold for teachers learning new ways of teaching.
"Used well, they help novice teachers develop confidence, fluency and professional judgement before gradually adapting and refining their practice," she said.
Wellington Regional Primary Principals Association president Shirley Porteous said teachers were under pressure and there was a risk some would simply work through new maths resources line by line instead of tailoring lessons to meet students' needs.
"Effective teaching is not reading from a script with kids but I would say the outside pressure is probably causing some of this in terms of the speed of change," she said.
Porteous said principals were worried about the potential rise of slides or scripts as the basis for lessons.
"It's absolutely something that we're aware of that is happening overseas and it's really important we don't let that happen here. That we stick to what we know is effective pedagogy to teach kids and it's not slide after slide after slide," she said.
"I want kids who walk in here everyday to not just be excited about play-time and lunch-time but actually enjoy being learners, life-long learners."
Andrew King from the Rural Schools Leadership Association said principals and teachers had been talking about the use of highly-scripted lessons.
"I know that people have seen such practice in Australian schools and are thinking and considering it in their schools," he said.
"Personally I have huge concerns on that because the focus is and should be about upskilling our teaching workforce to know the content and the knowledge to teach at each year level."
However, King said he wasn't seeing or hearing of scripted teaching in rural schools because their classrooms had children from different year levels so working from a single script would not work.
