I'm not aware of the formal rules. In Australia one wears one's full size decoraations with a lounge suit on Anzac Day. State functions with white tie are minatures plus collarette (eg DSO or AC) and/or sash. For black tie, events it will normally specify if minatures are to be worn. The exception seems to be the Order of Australia lapel pin.
10/4/08 at 8:34pm