New Zealand Death Records
As with births, New Zealand began the registration of European deaths in 1848, the collected records being kept by the Registrar General (as with other vital records, the registration of Maori deaths didn't become law until the 20th century). Given that European settlers didn't arrive in New Zealand until the early part of the 19th century, the vast majority of deaths there have been registered, a boon for anyone researching family history.
The Registrar General's IndexIf you have both the date of death and the full name (or at least the first name and surname) of the person you're researching, then searching the Registrar General's index should be easy. Unfortunately, the index isn't accessible online (you can request a search, although you'll have to pay for it), but some of the indexes can be found in larger public libraries in New Zealand. The indexes are kept alphabetically, year-by-year. Keep in mind that they go by date of registration of the death, rather than by the actual date of death. So if a person died in December, for example, the death might not have been registered until the following year.
Once you locate the entries you want, it's easy to apply for a certificate of death ($26 NZ) or a printout of the entry ($26 NZ for 1854-74, $20 NZ for 1874 onwards). You can download the request form from The Department of Internal Affairs.
Information on a Death CertificatePrior to 1875, there wasn't a great deal of information on the death certificate - simply where and when the person died, their first name and surname, sex, age and rank or profession, along with the cause of death, a very brief description of the deceased, where he lived and the name and signature of the registrar. For genealogists this offers some basic knowledge of the person, but it's spare on the detail you really need.
After 1875, things improve for anyone tracing family history, as death certificates became very full. As well as the information above, the certificate now contained the cause of death, the duration of the last illness, the name of the doctor and when he last saw the person, as well as the name of the deceased's father and mother (including her maiden name), when and where the deceased was buried and even the name and religion of the minister or witness. However, some of the most important new facts for a genealogist are how long the deceased had been in New Zealand, where he was born, where he'd married (including to whom and at what age) and the number and sex of the children. You can find plenty there to spur on your research in several different directions.
In 1912 the death certificate was amended yet again, adding the deceased's place of residence, how long had elapsed between the start of the final illness and death, and the widow's age (if she was still alive).
Quite obviously, for genealogists, the information given from 1875 onwards is a gold mine, allowing you to rapidly further your search. The "how long in New Zealand" entry in particular can be especially important for tracing immigrants.