I'm Australian - Visa for China Necessary if just Transiting?

I'm an Australian national with a valid passport. This year I'll be travelling to St. Kitts and Antigua for about a month, for which visas aren't required. I live in Australia and will travel via Guangzhou, China. My itinerary indicates that I'll only be there for about 4 hours before I catch my connecting flight.

Do I need to apply for a Chinese visa for the above? Or can I simply transit, document-free?