Makeup and sunscreen companies will no longer be allowed to hide nano-sized ingredients in their products after an environmental watchdog ruled that the relatively untested technology needed to be more closely watched in New Zealand.
It is the first time the Government has moved to regulate the booming market in nanomaterials - minuscule particles that have been manipulated to a billionth of a metre to make new properties.
Nanoparticles were increasingly being found in cosmetics products on New Zealand shelves, and were also found in car parts, washing machines and pesticides.
The Environmental Protection Agency (EPA) ruled that any cosmetic product for sale in New Zealand will have to list nano-scale ingredients on its label and highlight the ingredient by placing "nano" next to it in brackets.
Only a handful of nanoparticles have been flagged as potentially toxic, but environmental groups said regulatory gaps in New Zealand meant little was known about how nano ingredients were being used.
An EPA committee decided caution was needed because there was still scientific uncertainty about the potential effects of nano materials.
Green Party consumer affairs spokeswoman Mojo Mathers welcomed the change, saying it was essential for the public to be able to make informed decisions on products with new ingredients.
Sustainability Council spokeswoman Stephanie Howard said the EPA's decision was an important turning point because the proliferation of products with nano ingredients had raced ahead of regulation in New Zealand.
But she felt monitoring and regulation still lagged on nanotech, and she wanted the EPA to introduce a risk assessment regime.
A nanoparticle known as a fullerene, or a "buckyball", could be found in two brands of anti-ageing creams sold in New Zealand, despite widespread scientific concern about its negative health effects.
European authorities had banned the use of fullerenes in cosmetics until more testing had been carried out.
The EPA decision would not remove these products from the shelves but it would ensure shoppers knew they were buying products containing nano ingredients. The labelling change would not be required until 2015, which gave manufacturers time to sell off existing stock.
In the meantime, Ms Howard wanted a public register to be created which informed people of cosmetics products which contained nanoparticles.
The Cosmetic, Toiletry and Fragrance Association head Garth Wyllie, who advised the EPA on its decision, said he supported the new labelling scheme. But his support was for transparency. He didn't believe nanomaterials presented health and safety issues.
Johnson & Johnson spokeswoman Margaret Richards warned the new labelling requirements could stall cosmetics imports from the United States, because firms were often deterred by having to change their packaging.
SMALL MATTER OF CONCERN
What is nanotechnology?
The manipulation of matter to a billionth of a metre to give it novel properties, such as greater strength or durability.
Where can nano-scale ingredients be found in New Zealand?
In cosmetics products, pesticides, washing machines and car parts, among others.
Why is it used in cosmetics?
Nano ingredients can help kill bacteria or block UV rays.
What has the Environment Protection Agency ruled?
From July 2015, manufacturers of cosmetic and sunscreen products must say if their products contain nano ingredients.
Some nanoparticles, such as fullerenes, have been banned overseas because of concern they can penetrate deeply into the skin. Titanium oxide, which is found in sunscreens in its nano form, was found to rapidly corrode roofing iron after it rubbed off builders' skin.