Not sure where you're headed but
Shado-Lans Quarantine in Levin - an hour and a half north of Wellington - was very nice. We had a dog there, not a cat, but I saw some of the cats there. They have those carpeted towers to climb on in their room, and someone on staff can visit with them daily. Also, I remember them telling me that the two cats staying in one room together were from the same family, so yours may be able to stick together. All the rooms have their own adjoining outdoor fenced area. (My friend in NYC joked that my dog had more space in quarantine than she had in her little apt.) If you can handle the paperwork and the expense of the month of quarantine, I don't think they'd have too much trouble.