Consumer NZ is accusing some brands of "attacking the messenger" when it comes to their sunscreen testing.
It is standing by its testing practices after the Cancer Society this week criticised it after its Kids Pure SPF50 sunscreen was found to be SPF41.
Consumer also released another round of test results which found five sunscreens that have failed to meet SPF label claims.
Among them is Eco Tan Natural Coconut Sunscreen Untinted SPF30, which is shown to only give a low protection of SPF12.
Skinnies Kids Barefoot Babe SPF50 showed an SPF of 25.
"Skinnies went to market with this product after getting a valid test result for only one person," Consumer NZ chief executive Sue Chetwin said.
"It then found the SPF was degrading and had to reformulate."
Chetwin told Larry Williams that they had only tested it one person.
“To make a claim that you met the standard, it actually had to have been tested on 10 people.”
She says they made no attempt to recall it, and even though a new test shows the standard has improved, they still have not down the 10 person test.
“Before Skinnies comes out and makes these quite outrageous standards, they need to look at what they do need to do to get to the standard.
“What we’re trying to do is point out that in New Zealand, if you are out there buying sunscreen, they don’t have to reach the standard, but if you’re claiming to reach the standard, you’ve got to prove that you do.”
She says given the discrepancies, Consumer expected manufacturers to immediately review their testing programmes, rather than attack the messenger.
Chetwin says Consumer commissioned an accredited lab to conduct a 10-person test of the sunscreens according to the Australian and New Zealand voluntary standard.
"Two companies, Le Tan and We Are Feel Good Inc, provided lab reports showing their products had been tested on 10 subjects and met their label claims before being put on the market."
The Cancer Society this week questioned the testing methods used by Consumer NZ.
CEO Mike Kernaghan said Consumer decants the product in New Zealand before sending it for testing in Australia - whereas the society's own tests, where bottles are sent as is to the US, came back with a 60+ rating.
However, Chetwin responded by saying it was common for samples to be sent this way - and it was packed according to the lab's instructions.
"Preliminary results from three subjects showed it is likely to meet its SPF50+ label claims, but it hasn't provided a full 10-subject test."
She told Larry Williams that they have now agreed to do it.
Chetwin insists they have tested at an independent lab, but she doesn't mind if they go and test it there, as long as it is accredited.
University of Auckland Professor of Biostatistics Thomas Lumley says even in 10 person tests, there is still some variability.
He says there is potential for variation between batches and there are still questions over how big variations can be between labs.
Consumer NZ is asking the Government to make the sunscreen standard mandatory as part of the upcoming review of therapeutic products.