Chicken or egg though?
Happened in the Docklands (Melb), where MI for a while at least in (2003-5) limited loans to 50-70% LVR (across various lenders)
Were the price falls caused by these policies or was it market forces alone thta caused these polic shifts ie oversupply? If you believe the property market price escalation is primarily caused by the liberalisation of lending policies of MI & banks, then it follows their tightening (if that is what is actually happening) will cause a contraction in prices.
Ask yourself whether 'market forces' would have caused a more severe contraction in the docklands if insurers were lending at 80-100%.
If property market price escalation and more importantly, its rate of growth, is not controlled by insurers and lenders, then what is it caused by? 99.8% of the market borrow to buy property. Take the question to the logical extreme and ask yourself what property growth would be if lenders stopped lending altogether for a few years.
And keep in mind 'market forces' aren't just how many people want to buy and sell property, but also how many people want to lend money to Aussie borrowers at a particular perceived level of risk.
Further, I don't think valuers have much to do with it, because in the middle of the heat of 2003, Brisbane prices were going up 10% in some weeks. That's not due to a valuer, that's due to a lender approving a loan to a guy who put a property under contract for an all time high price 10% above last week's. Was that approval based on similar property sales? Hardly. In making that approval, did the lender and insurer take into consideration how much more untapped debt serviceability there might be in the economy? I think so.