A BITTER war of words has erupted between two of Hong Kong's top fashion designers that may end up in the courtroom. At the centre of the row is superstar Sally Yeh's wardrobe - and whether she owns genuine ''couture'' garments or copies. It all started with a seemingly innocuous comment by designer William Tang - nicknamed the ''bad boy'' of the Hong Kong fashion industry and an outspoken critic of the territory's copycat reputation - in a column for the Hong Kong Economic Journal. The last paragraph of the July 29 article insinuated the costumes for Yeh's recent blockbuster concerts bore a striking resemblance to high fashion designed by Martine Sitbon, Christian Lacroix and Gianni Versace. A week later, the Journal received a stern letter from lawyers representing Jonathan Chan, who designed the costumes worn by Yeh, denying they were copies. The letter demanded a full public apology from Tang and the Journal to avoid being hauled into court. ''I don't know why there is such a huge reaction,'' a perplexed Tang said. ''All I said in my column was we could be forgiven for thinking the clothes were from Martine Sitbon or Versace. I didn't even mention Jonathan Chan's name.'' Chan insists all 12 costumes he designed for Yeh's shows were originals of his label, Diva, and the outfits Tang referred to in his comments were Versace or Lacroix garments which Yeh picked up in Europe. ''I feel most uncomfortable because he [Tang] doesn't even talk to me first. He just writes what he thinks,'' Chan said. ''This is a general insult for people in the design field in Hong Kong, and he's part of it, too. What he said is unjustified.'' But Tang is sticking to his guns. ''I feel bad because even people in China are saying Hong Kong has no culture, that we are only copycats. I was telling him [Chan] how I felt, not trying to condemn anybody,'' Tang said. ''I have known him for years, but I was making a general comment about design in Hong Kong and I knew designers would not be happy if they read it. ''But I am a writer as well as someone from the fashion trade and if I feel I have something to say, I must say it.'' That is not good enough for Chan or his lawyers, who have stipulated that unless a public apology is made, further action will be taken. ''We are completely against this article,'' Chan said. ''First of all, I think the guy who wrote it doesn't understand the concept of concert costumes. It is not something I do as part of my collection or to satisfy my own creativity. ''What we do is design something especially for the artiste. That is the key before any creativity or originality. ''That's my starting point with my argument, and I think an apology is due. I don't think it's fair because if people don't understand the article they will have a misconception. ''This guy [Tang] should think more before he criticises other people. And he should also check with me first because the one or two pieces he might be referring to were bought by Miss Yeh to wear and he should be able to see the difference between real and fake.'' Having designed in the past for Sandy Lam, Danny Chan and Leslie Cheung, Chan feels his reputation is at stake. ''I feel so strongly about it I will take this matter all the way,'' he said. Tang said: ''It was said very clearly during the concerts that all costumes were designed by Jonathan Chan. ''In a way I feel bad I raised this problem because I feel I've made trouble again. ''This is just reconfirming my image as the 'bad boy' of Hong Kong fashion. I was just telling the truth but every time I tell the truth I get into trouble.''