For high value shipments, there are extra steps you must take regardless of the carrier you're sending through. High value goods refer to items greater than or equal to $1000 NZD.
NZ Customs require a commercial invoice supplied with the package(s) you're sending. You must be registered with NZ Customs and your client code must stay visible when it goes through customs. You can register with NZ Customs here. The best way to display your NZ Customs client code would be to include it on your commercial invoice. GSS does not have a field for your client code on your automatically generated invoice. We recommend creating your own invoice for this purpose.
The value of items is determined on whether or not the items are going to the same receiver on the same flight. For example, if you are sending three separate consignments to the same receiver at the same time, NZ Customs will take the combined value of all shipments (even if the consignment numbers are different).
Depending on the country you're sending to, there may be further duty & tax charges on high value goods. On GSS you may select for the receiver of the goods to pay these but ultimately, responsibility for the payment remains with you. If the receiver fails to pay the charges they will be charged back to your account.