Another five sunscreens have failed to meet their SPF label claims, in the latest round of testing by Consumer NZ.
The untinted Eco Tan Natural Coconut Sunscreen claimed to be SPF30, but only gave low protection of SPF12 in the test.
The Skinnies Kids Barefoot Babe SPF50 product had an SPF of 25 according to the testing.
Consumer NZ chief executive Sue Chetwin said Skinnies put the product on the market after getting a valid test result for only one person.
It then found the SPF was degrading and had to reformulate the sunscreen.
Skinnies was retesting the reformulated sunscreen and preliminary results based on two subjects showed the reformulated product is likely to meet its SPF50 claim.
Three other products were labelled as SPF50+ and testing showed they were SPF 41 to 45.
Two companies, Le Tan and We Are Feel Good, provided lab reports showing their products had been tested on 10 subjects and met their label claims before being put on the market, Ms Chetwin said.
Meanwhile, the Cancer Society based the SPF claim for its Kids Pure Low Irritant Sun Lotion SPF50+ on a technical report that evaluated a 10-person test of a formula with the same active ingredients but different preservatives.
The technical report only included a three-person test of the sunscreen Consumer NZ tested.
As a result of Consumer NZ's findings, the Cancer Society sent the sunscreen to a US lab for testing.
"Preliminary results from three subjects showed it's likely to meet its SPF50+ label claims, but it hasn't provided a full 10-subject test," Ms Chetwin said.
Consumer NZ said the response from some manufacturers to the test results was alarming.
"Given the discrepancies we found, we'd expect manufacturers to immediately carry out a 10-person test of their products and review their testing programmes, rather than attack the messenger," Ms Chetwin said.
Consumer NZ wants the government to set a mandatory sunscreen standard.
Earlier this week, the Cancer Society said it was disputing some of the findings of Consumer NZ's sunscreen testing of its products.