Steps are also in place to help those unable to do it or shy-of the on-line process, and to engage with households which don't appear to be participating.
The organisation expected about 70 per cent will do it online, with the paper option common to the days of Census agents knocking at the front door to deliver the papers and then to collect them coming to an end.
While the Census covers a range of topics with questions chosen to elicit the information to help plan the country's needs, much interest will surround how close the national population gets to 5 million.
It reached 1 million in 1908, 2 million in 1952, 3 million in 1973, 4 million in 2003, and totalled 4,242,048 at the last Census in 2013.
The population of the five territorial local authorities in Hawke's Bay from Wairoa to the Tararua district was 167,979, and the Hawke's Bay Region, defined by the regional council boundaries excluding Tararua and including small parts of the Taupo and Rangitikei districts passed 150,000 for the first time.
While the population grew in Napier and Hastings it had decreased in the three outlying districts of Wairoa, Central Hawke's Bay and Tararua.
A 2003 forecast that it would reach 4.81 million in 2046 is proving to be way short of the mark, with StatsNZ estimating it was 4.79 million at the end of last June, and its population clock last night calculating it was almost 4.8 million.
The population is growing at a rate of about one person every 5 minutes and 6 seconds, with births averaging one every 8 minutes and 46 seconds, deaths averaging one every 17 minutes and 4 seconds, and net migration gain of one New Zealand resident every 7 minutes and 6 seconds.
Censuses are held every five years, but the schedule was put back two years when the 2011 count was unable to be done because of the Canterbury earthquake.