An Australian skincare company whose sunscreen failed to meet its SPF claims has pleaded guilty to two charges.

An investigation by the Commerce Commission into Ego Pharmaceuticals' two Sunsense sunscreens found they did not meet the SPF50+ advertised on the bottle.

AMA Laboratories, a testing facility in the US that produced the certification for the sunscreen was exposed in 2021 for defrauding customers with its lab results.

A law change this Thursday, with the commencement of the Sunscreen Act, will mean any company whose sunscreen product fails to meet its advertised SPF could be fined up to $600,000.

Consumer NZ Chief Executive Jon Duffy said this was not enough and New Zealand was falling behind Australia in sunscreen standards.

Duffy said companies often relied on tests that were several years old to justify their SPF claims.

Last year's annual test of sunscreens by Consumer NZ found only eight of the 21 tested met the SPF claims on their labels.

SunSmart NZ said the cost of skin cancer treatment in New Zealand was expected to grow to $295 million by 2025.