Air Asia are offering flights to Seoul, South Korea for $376. This is the cheapest this route has ever been other than that crazy Virgin/Singapore flight error.
Most flights have a short layover however for the adventurous there are flights with a 7-8 hour layover in KL, which is plenty of time to take a cheapo bus into KL for dinner/entertainment.
Use Google Flights, then click on the calendar to find the cheapest date. Seems booking directly via Air Asia is the cheapest way to go (banner on their homepage). Air Asia May Flight $376.
Melbourne-Seoul $411 Google Flights. Only 1 long layover on the way back.Only a handful of $511 dates left. (31/3)Perth-Seoul $507 Google Flights. Seems to be June only.
Gold Coast-Seoul $636 Google Flights. Pretty expensive but next best price is $1,200 on the other airlines. Better off getting a cheap flight domestically to Sydney.
Amazing price!!!