"Students are at school when UV radiation levels are at their peak, so it is vital to encourage comprehensive sun protection."
Professor Reeder said the study showed that while primary schools were becoming more sun smart, there was room for improvement.
"For example, only 58 per cent of our schools reported having a written sun protection policy ... We also found that sun-protective clothing, curriculum delivery and environmental shade emerged as the areas that schools were struggling with the most."
He said only 42 per cent of schools met the requirements for encouraging the use of protective clothing, such as long-sleeved and collared shirts, and only 54 per cent had sufficient shade or were working to increase shade within the next 12 months.
He felt it would help if providing shade was in all school building plans.
The Cancer Society's national SunSmart Schools Programme spokeswoman, Louise Sandford, said NZ had the highest rate of melanoma in the world. "It is important children are in a sunsafe environment."
She said only 22 per cent of schools were SunSmart Accredited, although many others were working towards accreditation.
Principals Federation president Paul Drummond said the results were "a little bit disturbing" and warranted scrutiny to see why some of the measures weren't being implemented.
It might be due to financial pressures preventing things such as shade cloths being installed, he said, but the results were a timely reminder for schools to look at how they do protected their students from the sun.
Education Minister Hekia Parata said the statistics were "very disappointing".
"I thought the sun-safe message was well documented ... We all know we have to be extremely careful when we are out the sun, therefore it is up to parents and boards of trustees to take all precautions to ensure our learners are protected while at school."