Science teachers are blaming a focus on reading, writing, and maths for their subject's bad results in a national study of primary and intermediate schools.
They also warned that ongoing poor performance in science could have dire consequences for society.
Their comments followed the publication of a National Monitoring Study of Student Achievement report that showed children in Year 8, the final year of primary and intermediate schooling, performed worse in science than any other subject.
The study said 20 percent of Year 8 children reached the expected level of achievement in science last year, about the same figure it found five years earlier.
Association of Primary Science Eductors national coordinator Sandy Jackson said she was disappointed "but not really that surprised" by the results.
"The main reason is the focus in a lot of primary schools in the last few years is on literacy and numeracy and science gets pushed to the side and not taught as much," she said.
Mrs Jackson said she was not sure if the government's decision to abandon its predecessor's national standards in reading, writing and maths would bring an improvement.
"Even before national standards there was a big push towards numeracy especially and that meant that the science went down. So there needs to be some incentive for schools to be teaching more science," she said.
Mrs Jackson said New Zealand would struggle if it did produce enough scientists and people who understood the discipline.
"It is really important. The word science means knowledge and you do science in everything you do. Every part of your life there's science involved," she said.
Chris Duggan, the founder and chief executive of science education trust The House of Science, said the result had huge implications for society.
"It's shocking and I'm sure that there'll be a lot of people very disappointed," she said.
"The Year 4s have improved slightly but the Year 8s it's still really, really bad. To look at that and see that 80 percent of our Year 8s are going into secondary school with insufficient science to allow secondary teachers to start teaching where they should, that's a real worry."
Ms Duggan said many years ago science teaching was well-supported with government-funded science advisors who worked with primary school teachers and specialist resources for use in science lessons.
But that support had not been available for a long time and in addition the introduction of the national standards in reading, writing and maths in 2010 had sidelined other areas of the curriculum, including science, she said.
"I've heard time again that primary teachers lack the confidence and lack the resources to deliver meaningful, hands-on science lessons," Ms Duggan said.
"Science isn't well resourced. We need a system that's really going to make science normal again in every classroom in our schools."
Ms Duggan said New Zealand needed more people who understood science.
"We need a population that has some basic level of scientific literacy, that can look at the world through scientific lenses and without that we're in trouble. We end up with people making uninformed decisions about themselves, which is not good, but even for their families, for society, and eventually the economy and the whole planet suffers."
Association of Intermediate and Middle Schools vice president Jonathon Tredray said the result was worse than expected.
He said science might be getting lost in project-based learning that covered several subjects at once, but teachers' confidence was also a problem.
"It's definitely teacher expectations, teacher knowledge. A lot of teachers don't have innate knowledge of the science, so it's self-perpetuating. They've come through school a bit scared of science or not knowing the wonderful values of science and so they haven't felt confident teaching it themselves."