National Nanotechnology Centre (Nanotec) expert Dr Weeraya Pakawech said the science had been used in Thailand for about three years and in products from clothes and textiles to cosmetics.

"Some things use nano products but some [claiming to do so] do not," she said.

Nanotechnology is among the newest sciences and it has only been 25 years since the development of scanning tunnelling microscopy, which allows scientists to enter the world of the atom. Its growth is rapid and applications are developing.

Nano means one-billionth. Nanotechnology deals in the world of the really microscopic - or between one-billionth and one-millionth of a metre.

Nanotec said the science had commercial potential for the textile industry. Researchers have used nano-particles of titanium dioxide as a coating on material to improve water and dirt resistance, reduce wrinkling and to protect them from bacteria and ultraviolet rays. The yellow shirts honouring His Majesty the King's accession to the throne use nanotechnology to improve waterproofing and bacterial protection.

The Thailand Textile Institute has been working with a team from Chulalongkorn University to test nano-textiles in anti-bacterial car seats.

In cosmetics there is nano-scale use of titanium dioxide in skincare and sunscreen lotions.

The nano-scale use of other substances makes cosmetics absorb better and deeper to increase effectiveness, Weeraya said. One product claiming to enlarge women's breasts was prohibited from advertising its nano properties by the Food and Drug Administration (FDA) because of exaggerated claims.

Weeraya warned that some cosmetics manufacturers use the term nanotechnology as a marketing ploy and to increase selling prices by as much as 15 per cent.

Consumers should exercise common sense when purchasing products claiming to use the technology.

"Only laboratory tests can tell if a product uses nanotechnology. Nanotech has no authority to check products ahead of introduction but if consumers suspect a claim is false they can submit it to the centre," she said.

Weeraya also said Nanotec would like to see mandatory product testing.

The centre is publishing a consumer guide, which suggests ways to check if products are genuine.

Thai Industrial Standards Institute bureau director Opas Isarasenarak said it had no

check for nanotechnology applications.

Products can be introduced without receiving institute approval and there is no authority to oversee nanotechnology products.

FDA cosmetics-control division director Wattana Akkaraeaktarin said suspicious consumers could report products to the agency.