Counterfeit diapers are damaging both the reputation and bottom line of Japanese manufacturers in China, with companies in Tokyo calling on local authorities to act. The booming Chinese market is proving a lucrative one for Japanese firms such as Daio Paper, which makes the hugely popular Goo.n line of disposable diapers. And because they are superior to Chinese products, that has elevated them to the status of a luxury product. That popularity, however, has made them a target for the fakers. The quality of the copies - the diaper looks like the genuine article and the packaging is indistinguishable - means that the counterfeiters can charge almost the same price as the real thing, between 155 and 185 yuan (HK$234). That figure is double the price in Japan, underlining the importance of the Chinese market to Japanese firms. It is only when the diapers are put to the test that the differences become clear. The copies are made of a rougher material and absorb less liquid. This has caused big problems for companies such as Daio Paper, as angry parents complain about the quality of diapers that they believed were genuine products. "In July, the customer support centre for our subsidiary received an inquiry from a consumer who regularly purchased our products," Shunsuke Fujii, a spokesman for the company, told the Sunday Morning Post . "They said they had bought our diapers, but that they were fakes." The local subsidiary, Elleair International China (Nantong), analysed the item and was able to confirm it was an imitation. "The quality of the product - such as its absorbency - was poor and we are very concerned," Fujii added. "These fake products damage our customers' trust in our name, so we cannot overlook this problem." Daio Paper quickly contacted trade authorities in China, with the Guangzhou Administration for Industry and Commerce working with the Japanese firm on the problem. Earlier this month, the Chinese authorities ordered the confiscation of thousands of fake products and fined the company that was manufacturing them. With demand in China for diapers booming - the Japan External Trade Organisation estimated the market size at 170 billion yen (HK$12.67 billion) in 2013, three times the amount of just five years ago - there is a strong financial incentive for more firms to create copies. Japanese firms have an excellent reputation for quality diapers and are expanding their production to meet global demand. For the domestic market, there is also surging demand for adult diapers, a product range that is also expected to find new markets overseas.