I think that you'll find that with the surge in their economy and generally better living standards over the past twenty years, the average height of the Chinese people has increased overall regardless of any north/south divide. A similar thing occured in Japan post war and in South Korea. The average height of younger South Koreans is significantly taller than their North Korean cousins, its something like 8cm. It's a question of diet.
That said the average height of a Chinese male beneath the age of 20 is a shade over 168 cms or about eight centimetres shorter than the average Australian or American.
These are fine figures and I'll be happy just to put them on plastic bases, along with my Kriegspiel miniatures. Everything else is on washers.
PS: Now for some strange reason (it might be a Darwinian response to the average height above/ below sea level of their homeland) but apparently the tallest average height for a male population below 20 is in the Netherlands (181 cm). So if we ever see a dedicated range of modern Dutch they'll need to be 30mm not 28mm.