As a general rule New Zealanders do not use their region name. Regions are a fairly modern invention (since 1989). They're mostly environmental agencies and are based on river catchment areas and as such are primarily concerned with environmental protection.
Provinces in New Zealand were abolished almost 150 years ago, and have no relevance nowadays apart from local public holidays. Some modern regions are similar to their ancient provinces, while some are not. Canterbury region is similar to the previous Canterbury province (which may explain one Cantabrian's assertion that Christchurch, Canterbury, New Zealand is correct - although it is more likely due to parochialism, or football). The old Auckland province however covers modern Northland, Auckland, Waikato, Bay of Plenty, and Gisborne regions.
The only time a region needs to be stated is when two towns have the same name such as Frankton, Manaia, or Waikawa, and to distinguish Palmerston North from Palmerston in Otago as Palmerston North was called Palmerston from 1866 to 1871.