The New Zealand Bankers Association (NZBA) has a web site promoting their activities, and providing generic information about situations faced by bank customers. The web site is here.
The NZBA recently released an FAQ containing information for Residential Red Zone residents, and their lawyers, on the perspective taken by banks on the Government's Red Zone offer. Information in the FAQ covers the complications that arise where mortgages are involved (no hard information), contacts in each of the member banks, short answers to questions about how the purchase price deposit will be treated, and what banks will expect of lawyers.
The FAQ can be downloaded in PDF format from here.