I'm travelling to HK in October (Grabbed some cheap flights via Cathay Pacific through this deal https://www.ozbargain.com.au/node/250579 a few months back) and just happened to check and see what the prices have done.
Dates of travel - Thursday 20th October - Tuesday 15th November 2016 - proof https://postimg.org/image/ddtsgx4lt/622572fb/ (you can select dates within this timeframe)
$519 (with a small stopover eg. - 2hrs MEL-HK, 5hrs HK-MEL) is cheap!
Deal seems to only be from Melbourne - Tullamarine, VIC, Australia (MEL)
Remember you can get a 'Lowest Airfare Guarantee' with Flightcentre if you'd like to buy, collect physical tickets, organise travel insurance etc from a human. http://www.flightcentre.com.au/lowest-airfare-guarantee
Same flight $519 from Skyscanner (Airasia.com) http://imgur.com/x9AEJhH
Edit: that was with bad layover times in Kuala Lumpar —> This is yours $519: http://imgur.com/xhATL6k