"Consumer Magazine are choosing to ignore these two passed SPF tests, implying Skinnies doesn't comply to a required test standard," the Van Arts said in a statement.
The couple, whose waterless sun gel products are made in NZ, said they created a sunscreen that wasn't watered down, greasy, or full of chemicals.
"We're a start-up Kiwi company that competes against multinational brands and all our products are tested both in labs and real life before we launch them," they said.
"We conducted our tests at the same laboratory as Consumer NZ and supplied both our initial test, and the follow-up one, to Consumer Magazine.
"These tests showed that Skinnies Kids SPF50 (barefoot babe) passed the SPF test on both occasions, so we're disappointed that Consumer have chosen to ignore these
results."
They admitted there was some degradation of SPF over time but applied expiry dates because of it.
The pair are launching a petition at parliament.nz today to get a Government-introduced testing standard for all sunscreens.
However, Consumer NZ chief executive Sue Chetwin said there was already an Australian-New Zealand standard but it was not mandatory.
Chetwin said Consumer NZ disputed Skinnies' claims and that the not-for-profit organisation's testing showed an SPF of 25, not 50.
"They went to market with their Skinnies Kids barefoot babe SPF50 after getting only one valid test result not the required 10 subjects.
"And then it found the SPF was degrading and had to reformulate. Then it didn't issue a recall of the affected batches.
"And it's now testing the reformulated sunscreen and their preliminary results on two subjects, not 10, show it's likely to meet the SPF50 claim."
Chetwin said the standard expected was to test the product on 10 people, with a minimum of at least three.
"The first one was based on one valid test result. Now their preliminary results are based on two test results - that's not even the minimum three much less 10.
"What they [Skinnies] are saying is there's no requirement to meet that standard in New Zealand and that's what the big issue is for us, and it should be mandatory that they all meet the standards.
"But nevertheless, if you make a claim, the claim has to be right."
Chetwin would not respond to claims that Consumer NZ decanted sunscreens into other bottles reducing their effectiveness, to send to the only lab in Australasia, Eurofins, for testing.
However, she said testing ranged between $10,000 and $15,000 per subject.