What is your advice for travellers interested in travel to New Zealand for 2023?

Book early! Especially if there are experiences that the travellers must do, there is an incredible amount of pending trips that have been postponed for a couple of years now, so 2023 will be a busy year. If you are planning to travel over the school holiday period (End of Dec to Early Feb) book well in advance.
Have travel insurance! We can help with that
Don't be scared of New Zealand's off-peak times - aka the shoulder seasons of spring and autumn. Large numbers of people will begin travelling again soon and if you'd like to avoid the crowds, try these quieter periods. They hold their own reward with spring being prime wildlife/farm animal spotting, not to mention the beautiful natives including rata and manuka coming into flower! Autumn is a time for crisp bluebird days and some of the calmest weather of the year. The beautiful fall colours are not to be missed, and are best seen around Hawkes Bay and Central Otago.