The delivery of census forms begins on Saturday.
Eight million forms and internet access codes are being distributed to nearly two million households by about 7000 collectors.
Census general manager Carol Slappendel says the operation is generally straightforward in urban centres but a real challenge in rural areas.
The census - the country's largest yet - is on Tuesday, 8 March.
It will be possible to complete the census online in either English or Maori.
