Upvote:10
The flight you're referring to flies from Singapore to Sydney, then on Canberra, then finally back to Singapore - picking up and dropping passengers at each stop.
For passengers flying from Singapore to Canberra, you do NOT clear immigration or customs in Sydney. However you DO need to exit the plane and take all of your carry-on items with you. You'll then need to pass through security (which means no liquids >100ml!), and then re-board the flight.
Transit security in Sydney is very fast, especially at the time this flight arrives, and airline staff will be on hand to make sure all passengers make it through before the flight continues on for its next leg to Canberra.
You do not need to collect your checked bags, and they will continue on to Canberra.
On arrival in Canberra you will need to go through immigration, collect any checked bags, and then through customs.