Four out of five Kiwi students are entering high school below the expected curriculum level in science.
The National Monitoring Study of Student Achievement, now the only measure of primary school achievement since national standards were abolished last year, has found that 94 per cent of students achieved at the expected level in science last year in Year 4, but this plunged to just 20 per cent in Year 8.
A Ministry of Education summary report says the results show that "progress is too slow" between Year 4 and Year 8, the last year of intermediate before students enter high school.
Chris Duggan, a former head of science at Tauranga Girls' College who started the non-profit House of Science agency to lift primary school science teaching in 2014, said the study showed that New Zealanders were "losing scientific literacy".
"We have known for years that primary school teachers are generally overall lacking in the confidence to teach meaningful science lessons, and there is also a huge lack of resources," she said.
"The Education Review Office found in 2012 that 73 per cent of our primary schools and intermediates do not have an effective science programme in place.
"We are seeing teachers who would love to teach science but are finding it difficult in a crowded curriculum with a lack of resources.
"This has huge implications for us as a country because what we are seeing is that by the time students get to high school they think science is too hard, it's not for them, and it's almost too late to remove that attitude by the time they are 13 or 14."
The national monitoring study surveys about 2000 students in 100 schools in both Years 4 and 8 in two or three subjects each year over a five-year cycle.
The latest reports, based on surveys in 2017, show that the numbers achieving at least at the expected level have actually improved in science, from 85 per cent to 94 per cent at Year 4 but only from 19 per cent to 20 per cent at Year 8.
Health and physical education (PE), the other subject covered this time, reported slight declines in numbers with "critical thinking" at the expected level, from 90 per cent to 88 per cent at Year 4 and from 46 per cent to 33 per cent at Year 8.
Surveys over the latest full five-year cycle show that solid majorities of students are achieving the expected level or above in Year 4 in all 11 primary school subjects, but by Year 8 most students are at the expected level in only five subjects: Arts, Technology, English Reading, English Listening and English Viewing.
Year 8 numbers achieving at the expected level are lowest in Science (20 per cent), Health and PE Critical Thinking (33 per cent), English Writing (35 per cent), Social Studies (38 per cent), Maths and Statistics (41 per cent) and Health and PE Learning through Movement (45 per cent).
The Ministry of Education's summary report says only 19 per cent of NZ teachers of Year 5 students had specialised in science, compared with 38 per cent of teachers at the same age level internationally.
Northcross Intermediate principal Jonathon Tredray, a spokesperson for the Association of Intermediate and Middle Schools, said schools were aware of this and offered help to teachers to cope with science-based school-wide study units such as rivers, weather and genetics.
"We have teachers who have an intimate knowledge of science work with other teachers ," he said.
Duggan, from House of Science, said new teaching resources and teacher professional development were focused on literacy and numeracy during the era of national standards from 2008 until last year. The standards covered only reading, writing and maths.
"Those are really important skills for their students to have, don't get me wrong," she said.
"But for children to be involved in learning those skills there needs to be a context that hooks the kids in, and science is such a perfect context."
But, she said, there was "no encouragement" for primary teachers to teach science.
"There used to be science advisers. They have long gone, so there is very little support for primary teachers," she said.
But Association of Primary Science Educators president Sandy Jackson, a teacher at King's School in Auckland, said teachers who got support did well in science.
"When teachers who are not very confident are given a little bit of incentive, of support, that changes for those people dramatically," she said.
Northcross Intermediate associate principal Wendy Johnston said "amazing support" for science teachers was available from the Liggins Institute at the University of Auckland and from Waikato University's Science Hub.