Scheme Aussie natives announced (4)
I believe the answer is:
ruse
'scheme' is the definition.
(thesaurus)
'aussie natives announced' is the wordplay.
'aussie natives' becomes 'roos' (short for kangaroo).
'announced' indicates a 'sounds like' (homophone) clue.
'roos' sounds like 'RUSE'.
(Other definitions for ruse that I've seen before include "trick played" , "Ploy, artifice" , "Sue to be a ploy" , "Subterfuge" , "Trick designed to deceive" .)