There are 32 Hawke's Bay schools currently accredited to the programme, with 18 more in the accreditation process.
"As a part of the accreditation there is a thermometer which is outside during the summer months that tells kids what the UV rate is," Mr McDonald said. The Government is being urged to do more to ensure children are sun-safe at school.
Lead author Associate Professor Tony Reeder, director of Otago University's Cancer Society Social and Behavioral Research Unit, has called on the Government to step up.
"It has become largely the responsibility of a charity, the Cancer Society of New Zealand, to introduce and sustain health promotion efforts in this area.
"We question though whether it should be a non-governmental group's role to shoulder the burden of achieving and sustaining universal uptake of SunSmart practices across all state and state-integrated primary schools."
Sun protection was a major health and safety issue, as sun exposure at an early age affected a child's lifetime potential to develop melanoma skin cancer. New Zealand has one of the highest melanoma rates in the world and Niwa is forecasting a return to normal summer conditions this year after last season's washout.
The study of 189 schools looked at 12 sun protection criteria drawn from the Cancer Society's SunSmart Schools Accreditation Programme - including shade provision, sunscreen, hats and clothing, and curriculum content.
Some 57 per cent of schools said cost was an obstacle to shade development and 31 per cent to sunscreen use. Thirteen per cent reported limited support from parents.
Cancer Society Sunsmart Schools programme coordinator Louise Sandford said there were barriers to schools implementing sunsmart initiatives.
"There's a difference between becoming signed up and being sun-smart."
The Cancer Society subsidised sunscreen for schools, but for some poorer schools even the subsidised cost could be a burden, she said.
New Zealand Principals Federation president Paul Drummond said most schools had sun-smart policies.
He added that the cost of providing shade at schools was prohibitive as it was not covered by schools' five-year capital funding programmes.
Staying Sun-smart
Slip, slop, slap and wrap.
Between the hours of 11am and 4pm in the daylight saving months, keep children out of the direct sun as much as possible - indoors and in the shade.
Even in the shade other SunSmart actions should be used, as UVR is reflected by surfaces such as concrete, water and sand.
Dress your child in a broad-brimmed hat and close-woven clothing that covers the arms, shoulders and legs.
Use a sun cover over children's pushchairs.
Plan in advance - if there is no available shade, create a shaded play area.
Use a SPF30+ broad spectrum sunscreen and reapply every two hours.
- Source: Sunsmart NZ