Hi Judy.
The problem with traditional food is that being such a young country we just take other cultures food and modify it.
Of course there are the Maori foods, (like KFC) but they are not in everyday use, except among some Maori of course.
Heres a link...
http://www.maorifood.com/
Generally meat pies are traditionally popular, and from extensive personal experience very good, they make energy packed lunches and are popular.
Vegemite is also an awesomely nutritiious food, used in sandwiches and also on toast with grilled cheese on top. Vegemite and honey is also nice.
From 2nd hand comments it seems that kiwis eat more vegies and less meat than Americans as well, but the same multinationals have infected our society in terms of convenience food as in America.
Hot chips, potatoe slices cooked in oil are also "traditional" and still popular. Afterall they provide the most cheapest food source out there. "Fish and chips" are also a staple in some places.
Otherwise i can't think of anything unique. Maybe Roast lamb or mutton as a meal with roast vegetables?