When gathering information, Smarter Homes suggests:
Read the Body Corporate Rules to check which areas of maintenance are the responsibility of all owners of the apartment building and which are the responsibility of individual owners. You should also ask to see the body corporate minutes.
Obtain a copy of the certificate of title from Land Information New Zealand (a lawyer or search agent can get this for you).
Check the District Plan and/or local council design guidelines as to what can be built on neighbouring sites. You don't want to lose privacy or views.
The Land Information Memorandum from your local council should tell you about rates, restrictions on use of the land/buildings, resource consents, sewage and stormwater pipes and environmental issues such as erosion, flooding and hazardous substances that might affect the site.
Contact the Weathertight Homes Resolution Service to see if any claim has been lodged on the building.
For an idea of price, look at other properties on the market, hire a valuer or buy information from the Quotable Value website.
Other considerations:
Ask who the architect, builder and developer were. If any have gone out of business this might indicate problems with the development.
Which way do the windows face? Is it insulated? Visit at different times of the day to see how the sun affects the apartment.
Are access areas well-lit and visible? Are there security cameras?
Check which doors and windows can be opened to let air in.
Does the neighbourhood feel safe? Are there bars, schools or workplaces nearby that might be noisy, smelly or dusty?
And, before you sign any agreement, seek legal advice.