My ten cents.
I was in London jumping up and down saying that it was unsustainable.
We had a murder outside our house and the estate agent lifted up the police tape to show someone round a 1.5 bedroom tiny appartment upstairs from us that was for sale for 450 GBP.
Yet still it sold.
House prices need to make sense in the context of the value that you get from living in the house otherwise it is just speculation. With this in mind, you need to look at long term rental vs buying.
In the UK it became cheaper to rent at one point (with all the economics and projected inflation, discounting of future returns etc, long term house price accumulation), at that was when the bubble burst... but not what caused the bubble to burst.
All bubbles are different to one another (something Greenspan said in the wake of the last bubble bursting - not that he is necessary a great person to quote at this point in history).
The UK bubble was a combination of speculation based
perceptions on population growth (it's not far off growth in Oz - and oz has space to use)
www.google.com/publicdata/explore?ds=wb-wdi&met=sp_pop_totl&idim=country:GBR&dl=en&hl=en&q=uk+populationstupid lending (aussie banks are not stupid but not great either and are dependent upon foreign creditors)
good news (bankers getting silly bonuses)
It ended when the banks were not able to lend as much, meaning they stopped the good news
Ultimately the same thing won't happen in the same way in Australia. However a few things look a bit wobbly....
1 Australian retail employs a lot of people and it's terribly uncompetitive and over priced
2 Australian retail pays huge rent on the properties that are owned by Aussie super funds
3 Aussie super funds are invested heavily in Aussie companies
4 Apart from mining. What is growing in the economy? And mining profits don't necessarily stay in Australia
5 The average house price to median wage ratio is extremely high
I know everyone will start banging on about immigration. You can't say that immigrants are unskilled impoverished and taking from society, whilst also maintaining that they are able to push the housing market up with their immense wealth....