Australia's "City of Light" (5)
I believe the answer is:
perth
'australia's city of light' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for perth that I've seen before include "Period (of effort)" , "Town at the head of the Tay estuary" , "Scottish/Australian city" , "City of Scotland" , "Home of fair maid" .)