This New Zealand work is in the public domain both in New Zealand and in other countries adhering to international copyright treaties, because its copyright has expired. According to the Copyright Act of 1994 [1][2] as elaborated on by the Copyright Task Force of the Library and Information Association of New Zealand[3] :
Type of material
Copyright has expired if ...
A
For photographs, manuscripts, archives, music scores, maps, paintings, and drawings published anonymously, under a pseudonym or the creator is unknown:
photo taken or work published prior to January 1, 1974