Archives New Zealand Wellington holds wills probated through the Wellington, Wanganui, Napier, New Plymouth, Palmerston North, Nelson and Blenheim Supreme Courts. For wills probated in other parts of New Zealand, you will need to contact one of the following offices:
Christchurch@archives.govt.nz (Canterbury and West Coast)
Dunedin@archives.govt.nz (Otago and Southland)
Auckland@archives.govt.nz (upper half of North Island)
The Archives New Zealand Personal Identity Research Guide can help researchers with this type of enquiry.