Consumer New Zealand is calling for the sunbed industry to be licensed, saying voluntary standards are not working.
Standards were revised last year and people under 18 are banned from using sunbeds, though the results of a survey show some operators' attitudes are still too relaxed.
Sunbeds have the potential to expose a person to as much as five times the dose of UV radiation received from the sun.
Consumer New Zealand sent a 16-year-old student to 10 sunbed sessions with operators in Wellington.
Only three operators asked her age, two of them calling her mother who gave permission and the third signing a consent form for her.
One of the operators did not warn the teenager to protect her eyes with goggles.