Answer:
A majority of New Zealanders celebrate Christmas as a family oriented holiday, gathering for a large family lunch on Christmas Day, and exchanging gifts. Some celebrate it as a Christian festival, by attending church.
Some eat food that is more usually associated with winter European meals, such as roast meat and steamed puddings, but others eat summer food. Fresh peas and other summer vegetables are associated with Christmas, as well as strawberries, cheesecake and pavlova with fresh whipped cream.
For those with non-christian and non-european ancestry it is a holiday with no festival associations.
Christmas Day and the day after which is called Boxing Day) are statutory holidays . Only essential (usually food based) services may be open on Christmas Day, but Boxing Day post-Christmas sales are a big part of the retail calendar. New Years Day and the 2nd of January are also statutory holidays and most people take the days between Christmas and New Year off work.
For most New Zealanders, Christmas is the start of a long summer holiday. Many companies shut down completely for two weeks or more, and this break is often called the Christmas holiday. When asked "What are you doing for Christmas?" it usually means, "for your summer holiday".