Basking in the runway spotlight at a Tokyo fashion show, next to the Y5 million ($A53,453) Russian sable coat is a cape of lowly polyester sewn with chinchilla that's being billed as "ecological fur." The cape, bolero and several other items by Japanese designer Chie Imai use real chinchilla and mink from fur farms.

But the fabric parts of the clothing use recycled polyester from Japanese plastic and pharmaceutical maker Teijin Ltd.

"We have not compromised quality. And tying ecology with fur is such a fascinating concept," Imai said.

"Ecological fur" sometimes refers to fake fur, but Imai uses real fur. Her so-called ecological designs use polyester strips and fabric with genuine fur. A bolero, for instance, has real fur trim, but the fabric parts and the lining are all recycled polyester.

Imai is the latest fur designer to use synthetic materials with fur - despite complaints from animal rights activists that the term "ecological" is a ploy to distract people from the mistreatment and cruelty of animals in the fur industry.

But Imai argues that fur itself is ecological because it can be worn for generations and "returns to the earth" as organic material and causes no pollution.

"We aren't destroying anything. Aren't you going to eat meat? Wear belts or shoes?" she said.

Imai's ecological fur - ranging in price from Y1.2 million ($A12,829) for the mink bolero to the Y8.4 million ($A89,801) chinchilla cape - allows her clientele, which includes the Japanese royal family and movie stars like Sarah Jessica Parker, to feel green, she said.

"They want to take part in being ecological, but it's hard for them to find a way to do it," Imai said at a Tokyo hotel, showing her 2008-2009 collection debuting her ecological fur.

Imai's ecological fur will be sold around the world later this year, including the US and Europe, she said.

Teijin's recycling technology produces some 7,000 tonnes a year of recycled polyester from used polyester clothing, said company spokesman Yoshihito Usami.

Old clothing is first broken down into bits as tiny as a rice grain, and processed with chemicals and heat to take out the colouring, buttons, zippers and other foreign objects to produce the basic ingredient for polyester, dimethyl terephthalate, or DMT, he said.

That is then made into thread that gets spun into polyester fabric.

Recycling 3,000 T-shirts through such methods cuts carbon dioxide emissions by 77 per cent and energy consumption by 84 per cent, compared to making them from scratch, according to Teijin.