"That's the sort of sunburn that raises your risk of developing melanoma later in life quite a lot," the council's Sun-Smart spokesman, Wayde Beckman, said yesterday.
"Use plenty of quality sunscreen, get into the shade in the middle of the day when the sun is fierce and definitely wear a hat and [protective] clothing."
Mr Beckman also warned that neither cloud nor cool wind gave protection against the sun's harmful ultraviolet rays.
"You can still get burned on a cloudy day. Reflections can intensify some of the UV rays as they pass through the cloud. Cloudy days can be as risky as a clear day."
He urged parents of teenagers to keep reminding them about sun-safety.
"Teenagers have got other things on their mind - they aren't great planners. Maybe slip that sunscreen and a hat into their bag to make sure it's always available."
Otago University research among schoolchildren in Years 4 and 8 found high rates of "sun-smart" knowledge, but comparatively low rates of sun-smart behaviour - a disconnection the researchers attribute to children soaking up the pro-tanning attitudes of friends and family.
A quarter sunbathed frequently, and two-thirds said they had been sunburned the previous summer.
"There is no such thing as a healthy tan," the Health Sponsorship Council and the Cancer Society say on their Sunsmart website.
"A tan is a sign that your skin has been damaged by UV radiation."
Skin cancer specialist Dr Mark Gray said many people continued to ignore or did not get sun-safety messages.
"New Zealanders very much have an attitude that it won't happen to them," he said.
"But with the statistics as high as they are, and showing no signs of declining, people who continue to ignore specialist advice are quite literally gambling with their life."
He said people should see a specialist as soon as they found a mole or lesion of concern, and should also have their moles checked and recorded regularly and a clear and consistent record kept.
SUN SAFETY
Cover up: wear clothing to protect your skin from the sun.
Sunscreen: use plenty, 15 minutes before going out and regularly during the day.
Hat: wide-brimmed.
Sunglasses: close-fitting wrap-arounds.
Source: www.sunsmart.org.nz.