If you are flying from the UK to Australia then you will probably have to have one break, but that will still leave you with one long "leg" of probably 15 to 17 hours.
Two of my family flew from UK to Australia and stopped at Dubai for a few hours.
I think the UK to Dubai leg was 5 or 6 hours, then the Dubai to Australia leg was I think 16 or 17 hours (cant remember the exact figures).
You could do two breaks, maybe Dubai, then Hong Kong, but then the total flight will probably take you a long time, probably 2 days or more.
Then you have the same problem coming back.
You can easily "lose" two days on the flight out, and the same on the flight back.
In fact I think you lose more going out as you are going forward on the time zone. My family members left on a certain day and did not land in Australia till two days later (flew off late Wednesday and landed on Friday I think)