I need to go to Hong kong on 18 oct and left on 24 oct but my passport exp date is on 6 mar 2015

Should I worry?, I heard that I cant pass the immigration if my passport expiration date is less than 6 months. But after read all the information above I just not sure about this. by the way I am from Thailand and have to go to Hong Kong twice a year for the trade fair and never have this issue before.