BNZ customers who want to have a face-to-face meeting to discuss a loan, get advice or open new accounts with one of its bankers will need to prove they are vaccinated from January 17.
But the bank will continue to offer over-the-counter services to all members of the public regardless of their vaccination status.
BNZ has also said all staff, contractors and suppliers will need to be fully vaccinated and provide their vaccination pass when visiting any BNZ site from January 17.
Dan Huggins, BNZ chief executive, said vaccination was the best way for it to keep its people and everyone it worked with safe.
"For customers, there's no change in how we serve them. All over-the-counter banking can still be done in-branch regardless of vaccination status, but for longer in-person appointments we will require customers to be fully vaccinated."
He said customers could continue to contact the bank on the phone or online to do most of their banking, including discussing their lending needs.
In branches the bank already requires customers to wear a mask and sign in with the contact tracing app or a physical contact tracing form. The bank also ensures physical distancing and has sneeze guards.
A BNZ spokesman said unvaccinated staff could continue to work from home, just as they had since the beginning of the pandemic.
The bank would be reviewing the policy over the next six months to make sure it was protecting its people and customers, and ensuring its staff could continue to deliver a great service, he added.
Last week ANZ said it was consulting on a proposal that would require its branch workers to be either vaccinated or undertake a rapid antigen test.
Chief executive Antonia Watson told the Herald last Wednesday that its customers would not need to be vaccinated to come into branches.
"We haven't been designated as an essential business under the supermarket or pharmacy rules. But we still feel like we are.
"We can't exclude a vulnerable customer that needs to come in and get cash and has chosen not to be vaccinated."
The New Zealand Bankers Association sought guidance from the Government on whether banks were an essential service but they have been classified as general retail.
That means it is up to individual banks to decide if they want to require customers to have vaccine passes if they come into branches which would also mean workers must be vaccinated.