You actually have a plethora to choose from:
Qantas International Business
Location details: Airside, Level 5 (entrance via Level 6 opposite Gate 15).
Opening hours: Daily 06:00-last departure
.
The Pier Business Class Lounge
Location details: Airside, Level 6 & 7, take the escalators after Immigration, and turn left immediately.
Opening hours: Daily 06:00-2330
.
The Wing Business Class Lounge
Location details: Airside, Level 5, reception near gates 62-66
Opening hours: Daily 05:30-last departure
.
G16 Lounge
Location details: Airside, Level 7, near gate 16
Opening hours: Daily 06:00-mid night
.
Sakura Lounge
Location details: Airside, close to Gate 40
Opening hours: Daily 06:00-16:00
.
The Travelers Lounge*
Location details: Airside, Departure Level, Terminal 2A
Opening hours: Daily 24 hours
Notes: * JL uses only for midnight departure
Operated by a third party on behalf of: Royal Jordanian, Japan Airlines
* At peak periods, access to certain lounges may be restricted due to capacity constraints. Access is available on the day of departure when the next onward flight is with a oneworld member airline. Access may not apply at a limited number of third party lounges.