Census forms may become a thing of the past as Stats NZ looks to rely on already existing information rather than the quinquennial survey.

The 2023 census was declared a success with 99 percent of the population counted.

But that number came from about four-and-a-half million people having filled out the forms and another half-million being represented through government data.

Stats NZ chief executive Mark Sowden said it was the second time that method had been used in New Zealand, the first was in 2018 after poor Census returns.

"The most important thing at the end of the day is how much data we can provide New Zealanders.

"The thing we call a Census was always designed to be a combination of the forms and this other data."

As the quality of administrative data improved there was less need for the survey that was conducted every five years, Sowden said.

"The data that we collect from forms will become less important to us over time, yes, as we get more and more of this admin data and the data is of a higher quality we definitely want to switch to using that.

"So that we're not going out to New Zealanders and bothering them and asking them to fill in forms if we don't need to."

Stats NZ would consult with the public in May about the future of the Census.

"The thing called a Census with all of the branding and marketing and things will probably disappear over time," Sowden said.

In many cases the quality of administrative data was better than the survey, he said.

"There will always be a case for some surveying, so some going to doors asking New Zealanders for data, because there's some data, like around mould that New Zealanders have in their houses that we'll just never get admin data for."

But he said data collection through the survey was getting more difficult, and more expensive.

And Sowden said they would eventually be able to provide more regular information, potentially annually, through using administrative data.

Main image (Supplied/Stats NZ): Stats NZ will consult next month on the future of the Census.