Australian ones are sporting (5)
I believe the answer is:
rules
'australian ones' is the definition.
Although both the answer and definition are plural nouns, I cannot see how one could define the other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for rules that I've seen before include "In Australia, football" , "controls" , "See 7" , "game in Australia" , "Regulations, precepts" .)