The Cancer Society is being asked to recall all batches of one of its sunblocks because it doesn't give people the protection claimed on the label.

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.

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.