Depends on the last departure port - SIN is OK, -- HKG, CGK (depending on airline) are not.
You still can you just need to know the rules, and is more difficult if transiting.
On my last visit to TPE, I purchased duty free inbound to TPE, then put it in checked luggage for TPE-HKG (3-day stopover), then again for HKG-MEL-SYD.
No problems whatsoever as in checked luggage.
Australian flights generally have secondary baggage checks just before boarding specifically to check for luggage before boarding.
In SIN this is done as you go into the secure departure gate, then their is a table for purchased duty free.
In HKG this is done as you are about to board the plane, so any duty free would be confiscated (note generally they will check BP and wont sell it to you in HKG)