Welcome to WebmasterWorld Guest from 184.108.40.206
If you search for "Wellington Restaurants", do you get local results for Wellington NZ, or Wellington in Florida?
You can force NZ results by appending &gl=nz to the search querystring, this shows results for NZ even when searching on google.com
How about adding site:.nz to a search this forces just .nz (including all second level domains such as .co.nz) sites to show.
...but other than that I see no reason for my being shown Japanese results...