There isn't one set of rules that every country follows. What applies for Australians doesn't necessarily apply to Canadians or Brits or Kiwis, etc.

For what it's worth:-

Australians must comply with the normal I.D. requirements to apply for a full passport to replace a lost or stolen passport. If they cannot meet the normal I.D. requirements, Australian embassies / consulates will issue an emergency passport. Emergency passports are valid for only 2 weeks. No country in the world will issue a visa to the holder of an emergency passport. However most countries will allow travellers to exit the country using an emergency passport.

In other words, an Australian emergency passport would allow an Australian citizen to depart China and return to Australia.