New Zealand is a very young country therefore is not really reknown for it's old architecture. Some places in the South Island have some history, however Auckland has very few examples of old buildings.
You can find a few in the Parnell area, and it's a very nice place to walk around.
There are nice shops, in a village setting, old wooden buildings. If you have the time, walk up the hill to the top and visit the cathedral which is more modern styling.