Fast route for terminal transfer at brisbane

I have my flight from Sydney to brisbane and than to Hong Kong. I have only 1.30 hours of layover to change terminal and immigration procedures. Which is fastest way to change the terminal and complete my procedures so as not to miss the connecting flight. I will fly by qantas.

Both boarding passes will be issued in Sydney; bags will be checked through to Hong Kong. On arrival in Brisbane, proceed directly to the terminal transfer bus and present your boarding pass; this bus service is free of charge, and is a relatively short run, so you will have enough time to get to the international terminal to go through immigration and make your way to your gate.

There's free shuttle bus running between domestic and international terminal every 15mins I believe. There's also the free airpark shuttle bus that will run from domestic terminal to international one before heading to the car park, which most of the time, the driver will happy to let you get on board.

The bus is quite quick.

90mins is adequate to get across in BNE, unless your flight is delayed. International at Brisbane is incredibly fast with smart gates.