The official Australian Land Cover can be located here. However, it's a WMS only. You may be able to contact GeoScience Australia for a raster file.
The Land Cover map service includes information derived from the
Dynamic Land Cover Dataset (2000-2008) containing Enhanced Vegetation
Index (EVI) information. The service provides a base-line for
identifying and reporting on change and trends in vegetation cover and
extent. It is a cached service with a Web Mercator Projection.
A preview of the WMS can be found here.
In addition, there is also a land use dataset. While strictly speaking land use is not the same as land cover, they can be similar. Here is the official Australian Land Use dataset. It's a raster grid which has classified land uses across the entire country. The description:
The Land use of Australia 2010-11 is the latest in a series of digital
national land use maps at national scale. Agricultural land uses and
their spatial distributions are based on the Australian Bureau of
Statistics' 2010-11 agricultural census data. The spatial distribution
of the agricultural land uses is modelled and was determined using
Advanced Very High Resolution Radiometer (AVHRR) satellite imagery
with training data to make agricultural land use allocations. The
non-agricultural land uses are drawn from existing digital maps
covering seven themes: topographic features, catchment scale land use,
protected areas, World Heritage Areas, tenure, forest type and
A preview of the dataset can be found here.