There is a large community in New Zealand of cat welfare groups and groups that can help you care for your pet.
Some groups who can help are:
SPCA Wanganui - for Animal Welfare, stray cat rescue, adoptions
CHARM Animal Rescue- for wild/stray cat rescue
RNZSPCA - Animal Welfare
Kittycat Fixers - Desexing Assistance
Help Someone Fix Their Pet Cat or Dog - Desexing Assistance
Humane Society of New Zealand- Desexing Assistance