250KT IAS BLW 10000
Found the reference in AIP ENR 1.1 - 102 "Aircraft Speeds."
Applies to IFR and VFR a/c operating in Class C,D,E,GAAP and Class G airspace.
Nonsense.
re-read AIP ENR 80.
No speed restrictions for IFR aircraft in A and C airspace EXCEPT at Sydney Brisbane Melbourne and Gold Coast ( see ERSA special procedures)