This is an option provided by NZ Couriers for their parcels (only their parcels) to be delivered by a Residential Delivery zone sub-contractor.
You will need to use their Tools menu item to see if your address requires the purchase of a Residential Delivery zone ticket.
Check it out at www.nzcouriers.co.nz/address_checker.html
This new Residential Delivery charge is now included in all NZ Couriers prices - nothing extra to pay!
Generally, deliveries to a Business Delivery zone do not require this extra ticket.