Millions of letters with unique logon codes and online instructions are ready to be sent out across Australia ahead of the August 9 Census.
More than two thirds of Australian households are this year expected to answer the compulsory 61-question survey online, while remote residents will receive the traditional paper version to return through the post.
In addition 38,000 field officers will doorknock Australian homes as a reminder to submit a paper form or help out the less tech savvy.
NSW Census director Liz Bolzan said the demographic snapshot, gathered every five years, offers "a descriptive count of everyone in Australia on the one night, and of their dwellings".
"It's the basis of our population estimates so it's critical for our electoral system and distribution of government funds," Ms Bolzan said.
The Census sheds light on small geographic areas on topics including education and English proficiency and helps determine "where schools, hospitals and roads need to go", she said.
Respondent names and addresses will be retained for up to four years after collection, previously they were destroyed after 18 months.
"They will be destroyed earlier than this if there is no longer any community benefit in their retention," Ms Bolzan said, adding that combining the data with other surveys can present "a richer and more dynamic statistical picture of Australia".
Religious affiliation is the only non-compulsory question and this year 'No Religion' will be at the top of the options list, in line with international practice.
Almost 4.8 million people (22.3 per cent of respondents) selected No Religion in the last Census, while 25.3 per cent elected Catholic.
"As the second most popular option in 2011, it doesn't make sense to have it mixed in with the religions," Ms Bolzan said.
Going digital had saved $100 million in production costs, she said.
A penalty of $180 per day will be enforced after reminder letters and field staff visits cease in mid-September.
