"In conclusion, the data presented should provide more than enough evidence to suggest that Australia’s residential property market (specifically land market) is vastly overvalued, driven by debt-financed speculation and the relative non-taxation of land rent. While land bubbles have been a continual feature of the Australian economy, what separates this cycle is the relative enormity of the boom in both land values and private debt. A smaller private debt to GDP ratio during the 1880s and 1920s was enough to produce two devastating depressions, including a number of recessions during the mid-1970s, early 1980s and early 1990s."
See The History of Australian Property Values
A response to this is on Property Observer, plus a debate here.