There are several births listed at BDM Historical Records (http://bdmhistoricalrecords.identityservices.govt.nz/home/
) for this couple with the spelling KIRDY. I didn't check alternate spellings, but you should, and look for the marriage there, too.
You can purchase copies of registrations online at that site (or by other means if you wish). Get the printout, not the legal certificate, for family history purposes.
Hope this helps. :-)
Kaiwaka, Northland, New Zealandhttp://freepages.genealogy.rootsweb.ancestry.com/~wendyh65/