Hugh,
The scenario discussed of China needing food and invading neighbors to do so is the topic of a Book series, the first of which is called Tomorrow, When the War Began. It was also made into a movie, which removed much of the country specific aspects. The basic premise being that China required farming land to feed its population and so invades Australia, because the rich, greedy, Australians are wasting their territory and the Chinese will show them how to better use their assets. The Chinese Army is greatly supplemented with conscripts and volunteers, who are offered land to farm on once they steal it from the conquered Aussies. Cargo ships are used to launch a surprise attack that quickly overwhelms the Aussie defenses, and ground troops then move in to secure the territory. America is blackmailed by China to not directly intervene under threat of Economic war. While written for a young adult audience, the author does a great job laying out a plausible scenario and the Resistance movement that springs up. – Dan