The retailer, owned by Fast Retailing Group, said its Super Cool Biz collection will help people stay cool with less air conditioning during the summer months.

Japan's Ministry of the Environment first started encouraging businesses to set air conditioners to 28ºC throughout the summer months five years ago. Its 'Cool Biz' campaign was designed to ensure that office workers could work in comfort in the face of higher indoor temperatures, and has now been re-named Super Cool Biz.

The Government campaign will allow workers to dress more casually than before Uniqlo said.

The company's launch includes a range of jackets, shirts, cut and sewns, pants, innerwear and underwear. Special items include polo shirts with additional deodorizing capabilities, and a bra top garment with a built-in bra to help to cut down on the number of layers worn.