I've said it before and i'll say it again, there will not be a USA style housing crash in Australian property.
1/ Most USA loans are non-recourse
2/ People in the USA relocate far more often for work (think a bucket where water sloshes from one side to the other).
There are over 100+ tier 1 cities in the USA and people will move about on a regular basis (not talking the collapse of Detroit style....just regular moving from NY to Atlanta for a new job style).
The closest thing we in Australia have is the mining boom/collapse in Perth where miners/construction people have vacated Perth to move east to take up construction jobs in "infrastructure" projects causing rents to fall.
But there is no way that 30% of Sydneysiders are moving to Perth in the next 24 months.......no matter how bad the economy gets in Sydney.