In US dollars, that's about $400 billion, quite a significant amount of money for a relatively small economy.

Here's something else for policy makers to worry about as they attempt to engineer a soft landing in Australia's property market.

The country's lenders could be sitting on A$500 billion ($402 billion) of "liar loans," or mortgages obtained on inaccurate financial information, according to an estimate from UBS Group AG.

A survey by the firm of 907 Australians who took out a mortgage in the last 12 months found only 67 percent stated their application was "completely factual and accurate," down from 72 percent the previous year. The most common inaccuracies were overstating income and understating living expenses, the survey found.