Does Australia have a housing shortage?

Why are property prices so expensive in Australia? Do we have a land shortage? As we have 7,617,930 square kilometres of landmass and we have 3700km of coastland on the eastern seaboard. how could anyone claim that we have a land shortage?


Check out the capital cities on Google Maps. Do we really have a land shortage around capital cities? 

Maybe we have lack of reasonable town planning, but we certainly have a huge continent and a small population so why is land so expensive in Australia?

As we have huge landmass on eastern seaboard why does 40% of our population reside in Sydney and Melbourne? Why has the government not done appropriate town planning to create cities along the eastern seaboard by providing appropriate incentives rather than concentrating population in our megacities?

This is completely different to countries in Europe and in the US, there the population is spread out and housing is far more affordable: 


Could our Australian government create policies to make housing more affordable? All around US and Europe their population is dispersed over many smaller towns rather than concentrated in major capital cities like we have in Australia. Could government offer businesses tax incentives to create jobs and kick start small towns? Of course they could, it is just that there is no political will to take on the big lobby groups that have a vested interest to keep property prices high.




Do we have a shortage of properties in Australia?
http://www.censusdata.abs.gov.au/census_services/getproduct/census/2011/quickstat/0
http://www.smh.com.au/business/housing-shortage-all-smoke-and-mirrors-20120622-20szh.html
From 2011 Census we can see that there were 934,470 dwelling unoccupied, if there is a housing shortage why are there so many properties unoccupied?