http://www.railpage.com.au/f-p1150941.htm#1150941
Especially this bit:
http://www.comlaw.gov.au/ComLaw/Legisla ... E2001A38BBI just contacted ACMA about the recording of scanner devices.
The guy I spoke to says there is NO offense against recording audio heard from the scanner.
He also said to take a look at Part 2-1 of the Telecommunications (Interception and Access) Act 1979
So it seems that we are allowed to record audio from the scanner after all