If a document in New Zealand is of such a public nature as to be admissible in evidence in New Zealand on its mere production from proper custody, a copy of, or extract from, it is admissible in evidence if the copy or extract:
(a) is proved to be an examined copy or extract; or
(b) purports to be signed and certified as a true copy or
extract by a New Zealand officer who certifies that he or she has custody of
it.