Hi tracn4
Have you already checked the NZ Birth index (online) ?
I had a look for John Ivan SMITH (between 1895 and 1905)
but found nothing.

Perhaps he was born outside of New Zealand ?
His NZ marriage record would include parents names and is perhaps the best source of information, given that John Ivan would have supplied those details himself.
[His death record should also state his parents' names - but bear in mind, that information has been supplied by a "third party" - the informant to his death - who may or may not, have got the details correct.]
Lu