The housing affordability crisis is a structural issue. It's not driven by mass sentiment in normal residential loans as found in the US and Ireland (buy your home, sell for a profit!) with irresponsible lending like 100% mortgages or allowing minimum wage earners to own. And if all goes wrong, just post your keys with a formal bankruptcy letter into the bank and start again.

Land is artificially limited, resulting in very high urban prices. We're almost unique (aside from Canada) in the fact that all the nice areas are in and around the capital cities as that's where the majority of decent paying jobs are. We have fairly prudent lending controls.

What the current media sentiment could do however is;

1) Get investors scared and sell off their properties. Especially as Labour talked about reforming NG.

2) This sudden influx of properties (the majority of investors are already up their eyeballs in debt, and can't afford to upkeep the repayments without renters or the NG reducing the losses)

3) The influx of properties will lead to a nominal decline in house prices for a couple of quarters (so by 2017). Then now that people see house prices can go down, they will panic sell. Since most investors rely on NG to minimise losses in the hope for a capital gain, they're not going to accumulate more properties. Current mortgages in Sydney already pay 70% of their income, on average! - so there won't be many new FHB or people upgrading.

4) This sell off will also increase the supply of rentals, depressing prices. This means renters will have a wider range of properties to choose from and for cheaper. So, even for positively geared investors - housing is a less attractive (and may even put them behind in their mortgage repayments). And it'll stop new investors entering the market, without NG to offset the losses. So this will incur a second round of unloading investment properties, worsening the cycle of falling house prices.