More than 7000 officials began to deliver Census forms door-to-door on Saturday.
The country's largest information gathering exercise will take place on 5 March. It was deferred for two years due to the 2011 Christchurch earthquake.
This year's Census is the most expensive to date, with a budget of $90 million - $12 million more than the one conducted in 2006.
Everyone in New Zealand on 5 March, including overseas visitors, must be included on a form.
Census officials want the help of leaders from the Maori, Pacific, Asian and Indian communities. These groups, as well as the country's youth, are the least likely to fill out their forms.
Community liaison team leader Luke Crawford says census officials are reaching out to community leaders to remind people about the importance of the exercise.
He said young people are being targeted through social media to encourage them to take part.
Statistics New Zealand expects more than 2 million New Zealanders will complete the forms online, which it says is a secure and easy option.
An internet access code will be included with the forms to allow people to complete them electronically.
Once an online form has been completed, collectors will be sent a text confirming they don't need to return to pick up the physical document.