Thanks all for the advice.
WorldLux - the question is around the respective airlines allowing me to board flights when my Aus passport has less than six months on it. I'm very glad it's clear to you that I'll be fine! I just don't know how strict the airlines might choose to be, so wanted to ask some experts.
Redadeco, thanks for checking on that website, I'd not heard of TravelDoc before. I entered in my exact criteria (including that I'm only transiting HEL and HKG) and it said I was good to go. It still said that when I only entered the details of my Australian passport!
Many thanks for your help.