Can anyone refer to the reliable and freely available point location spatial data source of the cities of New Zealand?
You could set up an account with Land Information New Zealand--LINZ Data Service
Once you log in, hit browse data.
The select Gazetteer option. That should show you three options. Select NZ Place Names (NZGB) and the click on the plus sign. This will select all values from the dataset.
Then from the top right hand corner, click download.
Select csv file option to down load.
Open in your spreadsheet application.
Look for the feat_type column. Sort based on that column. Look for suburb, city, town, village. I would double check each type of item in that column to see if there is any more city/town like names.