Visa to visit Hong Kong for 1 day in September on Indian passport (Australian resident)

Hi, I have been invited to attend a single day training in Hong Kong in September. I am an Indian passport holder and an Australian permanent resident. My passport is valid until January 2014. Can you please tell me (1) Do I need one before entering Hong Kong, or can I get it on arrival. (2) My passport is valid until Jan 2014 - will this be a problem? Does it have to be valid for 6 months even for a 2 day visit? Please reply asap thanks.