香 港 日 本 文 化 協 會 --- 日 本 語 講 座 is THE BEST!
The program and teahers are very good. They have a high reputation in teaching Japanese. Classes fill up very fast and hard to get in if you come in late for registration. I have been taking their Japanese classes since 2004. Their tests and exams give you enough stress to study. They are very strict. If you don't pass the semester's exam, they will drop you off. The learning atmosphere is very nice. Students really go there for study and not fooling around. I never regret taking Japanese in this school and highly recommend it without any reservation.
http://www.japansociety-hk.org/chi/language.htm