Australia has taken its first step towards regulation of nanotechnology, with a call for food companies to disclose if they are including in their products particles invisible to the naked eye.

Nano-sized zinc is used as a preservative in food and packaging, and nano-sized clay particles make biodegradable sweet wrappers sturdy.

There has been no regulation on the use of nanotechnology -- particles manufactured at the scale of atoms and molecules. But the national food authority is now proposing that food companies should be required to disclose any nano-ingredients in their products.

The move follows comments by Science Minister Kim Carr that the Rudd Government intends to establish a regulatory framework for nanotechnology.

The lack of standards or testing for food, packaging and agricultural products containing nano-materials concerns scientists such as Nobel Prize-winning Swiss physicist Heinrich Rohrer, a pioneer of nanotechnology, because materials behave in unknown ways at the nano-scale.

"We do not yet know the risk," Dr Rohrer told The Australian in February.

Food Standards Australia New Zealand has called for public comment on draft amendments to a document outlining procedures companies must follow to have products approved for sale.

The move would oblige food companies to provide information on the size and shape of any nano-particles, and how they were incorporated into new products. But products would not require pre-approval safety testing nor labelling, and food packaging made with nano-materials was not covered.

The proposed changes were welcomed by Friends of the Earth nanotechnology spokeswoman Georgia Miller. "Until now FSANZ has been flying blind, with no way of knowing whether or not nano-foods are on sale," Ms Miller said.

A Friends of the Earth report released in March found 104 foods, food packaging and agriculture products containing nano-materials were on sale internationally.

FSANZ spokeswoman Lydia Buchtmann said labelling was a policy matter determined by the Health Department.

The department said it had no plans to make declaration of nano-materials mandatory.

Comments on the proposed changes should be provided to FSANZ by 6pm on October 29.