Australia's 10 million households are legally required to give the bureau of statistics information about their homes, religion, and income in the five-yearly snapshot on Tuesday night.
But politicians including independent senators Nick Xenophon and Jacqui Lambie say they'll risk a possible AU$180-a-day fine, and withhold their names and addresses.
This is despite census head Duncan Young promising Australians their data will be top secret.
"Hand on heart, the security set-up in order for people to submit their information -- it's encrypted all the way through from their browsers into the ABS's internal environment," he told the Nine Network.
"Then we go through the process of separation. The information is isolated so people who can access names can't access the rest."
The ABS has collected names and addresses since 1911 -- but it will now keep data for four years instead of 18 months.
Senator Xenophon said yesterday he would introduce legislation that made giving your name optional in the future.
"The ABS has failed to make a compelling case why names must be provided, and stored for four years, and unlike any other Census in this nation's history since that first Census on the 2nd of April 1911, all names will be turned into a code that ultimately can be used to identify you," he said.
"So, it seems, rather than being a snapshot of the nation, this Census will now morph into a mobile CCTV that follows every Australian."
"And it has come to this because of a woeful consultation process that not only lacked transparency, but some would say verged on the disingenuous."
Greens senators Scott Ludlam, Janet Rice, and Sarah Hanson-Young also said they'd leave their names and addresses off the census.
Former NSW deputy privacy commissioner Anna Johnston said she would boycott it all together.
"The short version is this: Yes to a national snapshot. No to detailed data-linking on individuals. That's not what a Census is for," Johnston wrote.
"Although there are certainly heightened privacy and security risks of accidental loss or malicious misuse with storing names and addresses, the deliberate privacy invasion starts with the use of that data to create a Statistical Linkage Key (SLK) for each individual, to use in linking data from other sources. Please don't believe that SLKs offer anonymity. SLKs are easy to generate, with the same standard used across multiple datasets."
But Small Business Minister Michael McCormack earlier labelled the controversy "much ado about nothing".
He said people already handed over more information when they logged into Facebook or signed up to a supermarket loyalty card -- a claim that was rejected by Nick Xenophon.
"Facebook doesn't fine you AU$180 a day until you comply," Senator Xenophon told the Nine Network ahead of the Tuesday night survey.
Cabinet minister Christopher Pyne accused the senator of engaging in a "tin-foil hat kind of politics" and damaging South Australia.
"If people follow his lead in South Australia and they are not counted, our population in South Australia will be under-represented and we could well lose a seat in the House of Representatives in the next redistribution," he told ABC radio.
Senator Xenophon's views are shared by Senator Lambie who is also worried about giving her name and address, given she's received death threats in the past.
But the man you may expect to not give his name -- David Leyonhjelm -- will be.
Despite declaring libertarians like him don't trust governments, and don't want to give them power, he won't be joining other crossbenchers.
"Broadly I'm sympathetic to that, but it is the law to provide your name and I wouldn't endorse breaking the law," Senator Leyonhjelm told ABC radio.
He said he was troubled the Australian Bureau of Statistics' decision to keep details for four years instead of 18 months, but was more concerned about the government's metadata laws that allow telcos to keep consumer details for two years.
Under Australia's data-retention laws, passed in March last year with the backing of the ruling Coalition and notional opposition Labor party, approved law-enforcement agencies are able to warrantlessly access two years' worth of customers' call records, location information, IP addresses, billing information, and other data stored by telcos.
"Our privacy is under threat and I think it is a serious issue, but relative to the metadata issue I see the census as relatively innocuous," Leyonhjelm said.
Both the Australian Bureau of Statistics and the government have attempted to hose down privacy concerns during the past week, and failed.
Last Wednesday, McCormack told reporters he was assured of the security procedures in place for handling Census data.
"Never been a breach, the ABS assures us that this won't happen into the future with this Census, and governments of all persuasion take that information and assurances on board," he said.
"The ABS has never had a privacy breach with Census data showing, and they have assured me as the minister responsible, they've assured the government, that they have every protocol in place, every process in place to ensure that there isn't a breach this time."
McCormack deflected questioning on whether Australia should have mandatory data breach notification laws, which has been promised and left unlegislated by both recent Labor and Coalition governments, to the Prime Minister and Cabinet.
Late last week it was revealed a claim made by the ABS that was rated by the Australian National Audit Office as being in its "Cyber Secure Zone", was removed from its site.
"The selected auditees had not achieved compliance with the Protective Security Policy Framework (PSPF) and the Australian Government Information Security Manual (ISM)," an ANAO spokesperson told ZDNet.
The ABS also confirmed last week that its IBM-developed online Census forms would not be able to handle names with accents or ligatures.
"Text is free-form, limited to ASCII printable characters, 100 character text limit each," an Australian Bureau of Statistics spokesperson said.
ABS said for people with names that contain characters that are not within the basic 95 permitted ASCII characters -- such as those with an acute, grave, or umlaut -- they should use the "most appropriate substitution".
Australians with mononyms, a single name, are recommended to enter the same name in both fields, or alternatively, put the mononym into one field with "any character" into the other field.
More on Census 2016
- Senator Xenophon refuses to complete Census
- ABS quietly drops Census data security claim
- ABS tells Australian government there will be no Census data breaches in future
- Census privacy risks are not what they seem
- Census should not collect names, everyone should have a number instead: Labor
- Australian online Census name fields restricted to ASCII printable characters