Most defence experts would actually turn the question around and ask: what would China gain that it cannot obtain far more cheaply through trade, diplomacy or coercion? At the moment, the answer is “not much.”
Australia already supplies China with many of the resources it needs, including iron ore, natural gas, agricultural products and critical minerals. Buying these resources is vastly cheaper than fighting a war to seize them. An invasion would destroy ports, mines and infrastructure, interrupt production for years, and likely trigger global sanctions that would severely damage China’s own economy.
Australia is also not the primary strategic objective of China’s military. Most analysts believe the Chinese military is primarily focused on what Beijing sees as its immediate security interests: Taiwan, the East China Sea and the South China Sea. These areas are close to China’s mainland, involve territorial claims, and are considered core national interests by the Chinese government. Australia is geographically distant and does not present the same strategic imperative.
An invasion would also be extraordinarily difficult. China would have to transport and continuously supply hundreds of thousands of troops across thousands of kilometres of ocean while protecting ships from submarines, aircraft and missiles. Even if an initial landing succeeded, occupying a continent nearly the size of the continental United States, with a population of more than 27 million and strong allies, would be an immense military undertaking. Few defence analysts consider this a realistic objective.
Where Australia does matter strategically is as a base for allied operations. In a conflict over Taiwan or elsewhere in the Indo-Pacific, Australia hosts important military facilities, intelligence assets and logistics hubs that support the United States and its allies. If China were ever in conflict with those countries, it might seek to disrupt those capabilities through cyberattacks, long-range missile strikes, attacks on shipping or other forms of coercion rather than attempting an invasion.
So the more realistic question is not, “Why would China invade Australia?” but, “How might Australia be affected if a wider conflict occurred in the Indo-Pacific?” Most contemporary defence planning is aimed at preparing for that latter scenario rather than defending against a full-scale occupation of Australia.
