Firstly, are you in NZ??
If so, the NZ Gazette provides a list of Registrations of Medical Practitioners. Unfortunately, it's in alphabetical order - not by location. These should be available at at city library - probably hidden in the stack room so you'll have to request them.
Otherwise, check Don Hansen's 'List of Lists'. This handy book lists holdings of phone directories, etc that are in libraries, etc throughout NZ. It will tell you if your local library has a phone book/Wises Directory for that time in their collection.
Otherwise, check the library collection for a Wises Directory for that time - it lists medical practitioners and, at that time, lists them by location.
Elli