I've always have Air NZ sort this for me before over the phone. Presumably things have gone down hill since Covid. On at least one occassion they have been particularly generous with me.

B1900 flight from HKK-CHC was cancelled due to inbound aircraft not arriving due to engineering. Managed to negotiate for a food voucher for the cafe, refund of the original fare paid, as well as a NZ-organised return shuttle for us all at no cost. I vaguely recall they may have also given some APD for the inconvenience too.