DESPITE their tiny flat nostrils and eyes that pop out like a goldfish, lightweight pedigrees like the shih tzu and white pekinese are bouncing their way inside young women's jacket pockets and designer leather shoulder bags. The equally tiny Yorkshire terrier, pomeranian and the lhasa apso are also trailing closely behind as the most sought after canine breeds both in this city and mainland China. As pet dealers will tell you, when it comes to choosing pedigree canine pets in Hong Kong, it is size, and not looks, that really matters. They say that smaller breeds are easier to groom and that toy and utility dogs have won the hearts of local pet lovers because they can be taken practically anyway and everywhere. Young Chinese women are particularly fond of small dogs because they are tiny and cute. ''After all, as the saying goes, pets tend to resemble their masters,'' one pet beauty consultant says. So gone are the days when the rich and famous raised and trained packs of working dogs like the alsatian, dobermann, or rottweiler, in their backyards to protect their mansion at Mid-Levels or Kowloon Tong. In fact, larger breeds such as the German shepherd, Afghan hound, old English sheep dogs, Irish setters and golden retrievers are disappearing fast in the territory. Though a small number of them can still be found inside air-conditioned homes. Pet shops and the adoption list of the RSPCA confirm the trend that the most sought-after breeds in the territory are tiny toy dogs. Medium size breeds like the American cocker spaniel, poodle and chow chow are also very popular. ''Smaller breeds are also probably easier to smuggle into China,'' one pet dealer said. ''When it comes to smuggling pets across the border, [illegal traders] have their ways.'' And it is probably true. While it is still illegal to own pet dogs in China, local supply of canine pets is, ironically, much dictated by what mainland bourgeois pet lovers want. ''In China, the tai-tais prefer white, tiny fluffy pekinese which symbolise wealth. There is no point in raising their own local ''Chinese dogs'' . . . they usually find their way to the dinner tables in food markets,'' another pet shop owner said. So, the dogs are bought to be seen in China and that may explain the popularity of breeds like shih tzu and pomeranian because they are generally regarded as ''clever'' and easy to discipline. Breeds like these have also championed in dog shows. According to canine literature, the shih tzu and lhasa apso fall into the utility category because they do not fit into other groups like hounds, gun dogs, terriers, toy or working dogs. They tend to have shrill barks, which can be irritating in the middle of the night, and require a lot of grooming. Though the miniature Yorkshire terriers are classified as toy dogs, they can sometimes get extremely vicious. Like the chihuahua, they are small and fragile so owners have to take extra precautions not to sit on them.