4-5%!? Aren’t central bank rates in the 0-1% range pretty much globally still? My mortgage is usually around one percent over the central bank rate so it’s been hovering around 1-1.5% for years now.

Yes. New Zealand has extremely high interest rates. I don't know why. My parents have told me that years ago they used to be even higher (10-15%).

See these banks for examples:

- https://www.kiwibank.co.nz/personal-banking/home-loans/

- https://www.asb.co.nz/home-loans-mortgages

- https://www.westpac.co.nz/home-loans-mortgages/

Also, it appears that our central bank has an interest rate of 1.5%: https://www.cnbc.com/2022/04/13/new-zealand-central-bank-hik....