ABS publishes this figure as 'Unoccupied private dwelling', not sure if most lastest report is free or paid though.
however google returned a 2009 article which might be of interest to you, http://www.theage.com.au/national/call-to-use-vacant-housing-20090701-d589.html
ONE in 10 Australian homes are "unoccupied", leading to calls from the federal Housing Minister for the homes to be put to better use.
Australian Bureau of Statistics figures show 830,378 dwellings are unoccupied.
Michael Matusik of Matusik Property Insights told The Age just under half of unoccupied housing was in capital cities, including about 120,000 properties in Melbourne.
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"If we just got that down to 5 per cent, we wouldn't have to build anything in Australia for five or six years," he said.
Federal Housing Minister Tanya Plibersek said it would be "terrific if fewer homes were unoccupied".
"Of course, a lot of those homes are holiday homes and as governments we have no right to make demands on people to use their own property in a particular way," she said.
"But obviously, where properties are simply sitting vacant as they are, particularly in some capital cities, it would be terrific if the owners of those properties thought twice about that - either developed them themselves or released them for someone else to develop and use."
News of the unoccupied housing was released at a Residential Development Council (RDC) lunch in Melbourne yesterday, which was also told of massive population and housing pressures in the Victorian capital.
