Home outdoor cooking apparatus for high heat cooking (wok, stir fry)
I don't know what's available in Australia, but in the US they market high-output outdoor burners for deep-frying turkeys. This one is marketed as 200,000 BTU, twice the output of the ones often used in Chinese restaurants. (This $1,000 restaurant wok is marketed as 90,000 BTU.) 

Most outdoor turkey fryers are marketed as 60,000 BTU, which will probably work reasonably well. They are decidedly not to be used indoors; YouTube has many videos of people setting their houses on fire.

Getting one in Australia may be a challenge, but they're very common in the US, and many kitchen stores and (oddly) hardware stores. I imagine you could have one shipped, though I'd verify that your propane tanks are compatible.