Seek legal advice about the property title. In particular you need to know about easements, including rights of way.
Buyers should make their offers conditional on a title search to identify any problems ahead of actual purchase.
If you are buying a household unit from someone who had the property built or built it themselves for the purpose of selling (called an on-seller) there are special requirements.
The on-seller must get the build signed off by the council (code compliance certificate) before completing the sale, or before allowing a purchaser to take possession of the household unit.
The only exception is if the on-seller and purchaser sign an agreement to waive this requirement.
Get the build signed off explains sign-off responsibilities.
The section of the New Zealand Law Society website can help you find a lawyer if you don’t have one.