Melbourne is typically 3 hours ahead of Hong Kong. When it's 12:00 PM in Melbourne, it's 9:00 AM in Hong Kong. Hong Kong does not observe daylight saving time, but Melbourne does.
During Australian daylight saving time (October to April), the difference is 3 hours. During Australian standard time (April to October), the difference is 2 hours.
Optimal meeting window: 11:00 AM - 5:00 PM Melbourne time (8:00 AM - 2:00 PM Hong Kong, or 9:00 AM - 3:00 PM in winter). Great overlap for business hours.
Melbourne has a large Hong Kong Chinese community, especially after the 1997 handover. The flight is about 9 hours, making it a popular business and tourism route between Australia and Asia.