People trying to complete the census online have been met with numerous error messages, told the system is "overloaded", and advised to call back in two days when they phone a hotline for information.
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By 8pm on Tuesday evening, it appeared the website abs.gov.au had crashed entirely, as an estimated 16 million people were due to log on to complete the census.
The Bendigo Advertiser Facebook page quickly filled with comments from people who had been waiting more than 20 minutes to submit their progress.
Others had completed the Census by 6pm and reported no issues.
Residents who refused to log on chose to complete their Census the old-fashioned way - with a paper and pen.
Some people were able to get through, but the errors appeared to escalate through the evening until the website stopped responding.
Others said they had tried to log in on multiple devices and still had no luck getting through, with one person claiming they had tried for two hours before they eventually gave up.
Earlier, the Bureau of Statistics advised anyone who had an error message to wait for around 20 minutes before logging back on.
On Tuesday evening, a Census spokesman said the online system was operating "as expected".
"We have currently received more than 1.3 million successful online submissions," the spokesman said.
"The system is operating smoothly and as expected. If anyone has experienced a local technical issue, they can try again on another device or contact the Census Inquiry Service on 1300 214 531 if they continue to have technical issues, or go to the Troubleshooting page of the Census website."
The Census Inquiry Service was deluged with calls on Tuesday evening, with Census advising anyone with issues to try calling back after August 10.