There is a fair bit of media writing on the subject. Such as this piece, (behind a paywall) https://www.interest.co.nz/banking/99537/westpac-nz-ceo-david-mclean-says-nz-banks-should-hold-higher-regulatory-capital, which talks about the issues banks are likely to face with the RBNZ requiring them to hold more capital.

The upshot, should these increased capital reserves be required, is that banks may need to:

• Put up interest rates. This is likely to happen across the board but will particularly affect those clients whose risk models show they are ‘riskier’, as banks will have to hold more capital for those clients
• Ration capital. Basically, this means banks will only lend to those where they can see they will get their required rate of return. It will be less about getting dollars out the door and more about making sure return hurdles are met.

If you want to read more about risk grading, we suggest you start with these articles:

• https://www.interest.co.nz/banking/97389/rbnz-proposes-significant-increase-bank-capital-requirements-will-eat-70-sectors
• https://www.harbourasset.co.nz/research-and-commentary/australian-banks-increased-capital-requirements-to-change-the-landscape/
• https://www.nzherald.co.nz/business/news/article.cfm?c_id=3&objectid=12222877