Article here.
The cost of sending a medium-sized letter will increase from $1.80 to $2.30, a large letter from $2.80 to $3.30, and an oversize item from $3.80 to $4.30. There will also be a 2.55 per cent increase for all domestic parcel products and services for commercial accounts, including CourierPost, Pace, and ParcelPost.
Postage in NZ is already seems very expensive. It's often more expensive to ship a package around your island than it is to ship something from China or the USA.
Maybe NZPost needs a proper overhaul. Mail is eventually going to just about cease, packages will keep going up due to online shopping.