I downloaded the latest suburb shapefiles from the latest census at
from the link
"State Suburbs ASGS Non ABS Structures Ed 2011 Digital Boundaries in ESRI Shapefile Format".
It has some missing polygons as when I open the shapefile in ArcGis for example it has holes around the Canberra region.
Im unsure how to best fill these holes are if there are tools out there to help me populate the holes with the correct polygons.