Consumer NZ is urging manufacturers relying on reports from the company to urgently retest their products.
New York-based AMA Laboratories owner Gabriel Letizia Jr admitted defrauding customers and causing sunscreens to be marketed on the basis of false reports.
Consumer NZ chief executive Jon Duffy said test reports from the US company had been used by manufacturers to justify the SPF claims for sunscreens sold to New Zealand consumers.
"For many years, manufacturers sent us test reports from AMA Labs when our tests found their sunscreens weren't up to standard. Manufacturers continued to rely on AMA Labs' results despite our tests showing products failed to meet their label claims," he said.
"With all the attention on this issue, it isn't reasonable for a manufacturer to maintain that an AMA Lab report is good evidence its product provides the protection claimed on the label. Consumers have been deceived."
With high melanoma rates in New Zealand, Kiwis were entitled to expect better, Duffy said.
Sunscreen tests were expensive and AMA was perhaps trying to save money, he said.
"What AMA labs were doing and what the owner has now pled guilty to doing is using far fewer humans in the testing process than what was required, which meant that the test results couldn't be averaged out as accurately as they should be and therefore couldn't be relied on."
In Consumer NZ's latest test, products that relied on results from AMA Labs include Ecosol Water Shield Sunscreen SPF50+, Natural Instinct Invisible Natural Sunscreen SPF30 and Sukin Suncare Sheer Touch Facial Sunscreen Untinted SPF30.
Duffy said any manufacturer that had relied on reports from AMA Labs should urgently retest its products.
He said people could find reliable products on Consumer NZ's website.
"We use labs that are not AMA and often we will use two labs and cross reference the results before we publish. So yes, there are sunscreens on the market that pass and and that information is available for free on consumer.org.nz so consumers can look it up there."
In a statement last week, the US Attorney's Office in the southern district of New York said Letizia had "schemed for decades to defraud customers".
From 1987 to April 2017, Letizia and senior staff defrauded customers of more than $63 million (US$46m).
Letizia is now facing up to seven years in prison. Four former AMA employees have previously pleaded guilty in relation to the fraud.
Last month, Consumer NZ lodged a complaint with the Commerce Commission, asking it to investigate sunscreens that failed to meet SPF claims.
Consumer NZ is calling for a mandatory standard that requires companies to regularly test their sunscreens at accredited labs.