

However, Sydney and Melbourne have some attributes which undermine their claims to global city status. Together, Sydney and Melbourne accounted for 42 per cent of Australia's gross domestic product in 2015-16, analysis by consultancy SGS Economics and Planning found. A Melbourne city-state would rank among the world's 50 biggest economies when measured in US dollars.

If Sydney were a city-state like Singapore it would rate among Asia's 10 largest economies and in the world's top 40.

Sydney's economic output topped $US300 billion last financial year, comparable to the gross domestic product of Hong Kong or Malaysia when measured in US dollars. It is easy to underestimate the economic clout of Melbourne and Sydney.
