Sydney is typically 3 hours ahead of Hong Kong. When it's 3:00 PM in Sydney, it's 12:00 PM in Hong Kong. Hong Kong does not observe daylight saving time, but Sydney does.
During Australian summer (October to April), Sydney is 3 hours ahead. During Australian winter (April to October), Sydney is only 2 hours ahead of Hong Kong.
Optimal meeting window: 10:00 AM - 6:00 PM Sydney time (7:00 AM - 3:00 PM Hong Kong in summer, 8:00 AM - 4:00 PM in winter). Good business hours overlap.
Hong Kong and Australia have strong trade and investment ties. Many Hong Kong businesses have expanded to Australia, and there's a large Hong Kong diaspora in Sydney.