The Everyday Sun Lotion SPF50+ is one of nine different brands which fell short in the latest round of testing by Consumer NZ, which covered 20 products.
Consumer NZ chief executive Sue Chetwin said the Cancer Society sunblock was tested at two different labs and scored a maximum sun protection factor of 30.
"As a result of our findings, the Cancer Society said it's withdrawing the batch of the product we tested. However, given the reports we have from two separate labs showing the sunscreen doesn't measure up to its claimed performance we've asked it to recall all batches of this product," Ms Chetwin said.
The Cancer Society's chief executive, Mike Kernaghan, said in a statement it had its sunscreen range "independently tested at an FDA-approved, ISO registered laboratory this year. The results show all products exceed their SPF claims. However, for the product batch being withdrawn (Everyday Very High Protection Sun Lotion SPF50+ with Expiry Oct 2021), Consumer NZ's results were significantly different.
"We would have preferred to retest the batch to prove its effectiveness, however that would take eight weeks so we've made the call to voluntarily withdraw the batch from retailers now."
The company remained "100 percent confident in the effectiveness of our sunscreen products", Mr Kernaghan said.
"I would like to reassure the public there is no health risk, because even at the lower level of SPF30 that batch still provides high protection."
Other sunscreens that failed to stand up their SPF50 claim were Sunsense Ultra, Banana Boat Dry Balance and Marine Blue Australia Dry Touch, with protection scores ranging from 20 to 26.
Five other products also fell short of their claims, but still had high protection from SPF 30 to 50.
Ms Chetwin said several companies, including the Cancer Society and Sunsense, had tested their products at AMA Laboratories, a sunscreen-testing facility in the US.
"In August 2019, the US Food and Drug Administration announced AMA's owner had been charged with, and some staff had pleaded guilty to, falsifying test results from 1987 to April 2017," she said.
"For many years, sunscreen companies have been sending us test results from AMA that conflicted with our tests. We think companies relying on these results should urgently re-test at a different lab to ensure they can back up claims."
Ms Chetwin said the government needed to urgently regulate sunscreens.
"New Zealand has one of the highest rates of skin cancer and melanoma in the world but the sunscreen standard remains voluntary."
In April, Consumer NZ made a submission to the Ministry of Health supporting sunscreens being required to comply with the Australian New Zealand standard.
Did NOT meet SPF claims on label
• Hawaiian Tropic Silk Hydration Sunscreen Lotion SPF50+ A Touch of Mango and Papaya, $12.22 (48.68SPF)
• Invisible Zinc Face + Body Mineral Sunscreen SPF50, $19.99 (46.48SPF)
• Natio Suncare Moisturising Sun Lotion SPF50+, $10.50 (38.78SPF)
• Frankie Apothecary Natural Sunscreen + Kawakawa and Antioxidant SPF50, $41.63 (38.42SPF)
• MooGoo Natural Sunscreen SPF40, $19.58 (38.42SPF)
• Cancer Society Everyday Sun Lotion SPF50+, $12.48 (30.6SPF)
• Marine Blue Australia Dry Touch Sunscreen Lotion SPF50+, $9.99 (26.4SPF)
• Sunsense Ultra SPF50+, $15.50 (25.82SPF)
• Banana Boat Dry Balance Sunscreen Lotion SPF50+, $9.71 (20.61SPF)
Met SPC claim but failed 'broad spectrum'
• Beauty Care Co Zinc Sport Sunscreen Lotion SPF50+B $7.00
• Surf Life Saving Sunscreen Lotion Dry Touch Formula SPF50 $12.99
• Wotnot Deeply Moisturising Sunscreen SPF30 $22.41
Met claim and passed broad spectrum
• La Roche-Posay Anthelios XL Ultra-Light Fluid SPF50+ $69.98
• Neutrogena Ultra Sheer Dry-Touch Sunscreen Lotion SPF50+ $25.87
• Nivea Sun Protect & Moisture Moisturising Sunscreen Lotion SPF50+ $11.00
• Smart365 Sun Sunscreen Lotion SPF50+A $7.20
• Oasis Sun Sport PA++++ SPF40 $34.99
• Badger Sport Unscented Natural Mineral Sunscreen Cream SPF35 $29.34
• My Sunshine Natural Sunscreen + Antioxidants SPF30 $29.98
• Solzinc Natural Sun Protection 30+ $50.00