Aussie tax
Just to add to Titan's post, there are past instances of people being declared resident of australia, for tax purposes, even though they didn't set foot into the country for two years.
Commuters are all sailing close to the wind - any serious audit will find you resident if you have your family in Oz.
And another wonderful thing about our(aussie) tax system - the burden of proof is on the taxpayer, not the ATO. You need to prove you are NOT a tax resident if they audit you! Good luck doing that if you have family, bank accounts, car, mobile accounts - anything in Australia other than investments! You are able to be resident of two countries, for tax purposes, so even spending more time in HKG than oz doesn't protect you.
Drunken air
all a double taxation agreement does is make tax collection administratively neat. You will still pay tax at the rate of the highest jurisdiction - presumably australia. If china wants their cut of tax, they will take it first and then you will have that amount 'credited' against the total aussie tax bill. So net effect is you pay full aussie tax, but china gets its hands on some of it!
Caveat Commuter!