In the just release IMF World Economic Outlook, as well as revising down growth estimates, they discuss macroprudential, highly relevant in the light of RBA comments. The main observations are:

1. there is evidence that macroprudential can assist in manage house price growth, and credit growth. Different settings should be applied to different types of purchases, e.g. differentiate first time buyers from multiple investors, but
2. it is less effective if the cause of extended price rises stems from overseas investors, who bypass local controls and credit policy, so specific separate measures may need to be used to target foreign investors
3. need to make sure business is not simply redirected to the non-bank sector, and
4. supply side issues also need to be addressed.

RBA please note! The comments in full from the IMF are below, and worth a read. In particular they cite a number of success stories, so macroprudential is perhaps more proven than many would like to admit.

Many countries—particularly those in the rebound group—have been actively using macroprudential tools to manage house price booms. The main macroprudential tools employed for this purpose are limits on loan-to-value ratios and debt-service to-income ratios and sectoral capital requirements. Such limits have long been in use in some economies, particularly in Asia.

For example, Hong Kong SAR has had a loan-to-value cap in place since the early 1990s and introduced a debt-service-to-income cap in 1994. In Korea, loan to-value limits were introduced in 2002, followed by debt-service-to-income limits in 2005. Recently, many other advanced and emerging market economies have followed the example of Hong Kong SAR and Korea. In some countries, such as Bulgaria, Malaysia, and Switzerland, higher risk weights or additional capital requirements have been imposed on mortgage loans with high loan-to-value ratios. Empirical studies thus far suggest that limits on loan-to-value and debt-service-to-income ratios have effectively cooled off both house price and credit growth in the short term.

Implementation of these tools has costs as well as benefits, so each needs to be designed carefully to target risky segments of mortgage loans and minimize unintended side effects. For instance, stricter loan-to value limits can be applied to differentiate speculators with multiple mortgage loans from first-time home buyers (as in, for example, Israel and Singapore) or to target regions or cities with exuberant house price appreciation (as in, for example, Korea). Regulators also should monitor whether credit operations move toward unregulated or loosely regulated entities and should expand the regulatory perimeter to address the leakages if necessary. For example, when sectoral macroprudential instruments are used to limit mortgage loans from domestic banks, they can be circumvented through a move to nonbanks (as in, for example, Korea) or foreign banks or branches (as in, for example, Bulgaria and Serbia). Macroprudential tools may also not be effective for targeting house price booms that are driven by increased demand from foreign cash inflows that bypass domestic credit intermediation. In such cases, other tools are needed. For instance, stamp duties have been imposed to cool down rising house prices in Hong Kong SAR and Singapore. Evidence shows that this measure has reduced house demand from foreigners, who were outside the loan-to-value and debt-service-to-income regulatory perimeters. In other instances, high house prices could reflect supply bottlenecks, which would need to be addressed through structural policies such as urban planning measures.