UPDATE A series of overseas hacking attacks on the Census website were part of a deliberate attempt to sabotage the national survey, the Australian Bureau of Statistics has revealed.

Millions of Australians were left angrily tapping their refresh button when the ABS Census website crashed on Tuesday night.

Speaking early Wednesday, ABS’s David Kalisch said the Census website had been attacked by hackers four times and was shut down as a precaution after the fourth attack.

“It was an attack, and we believe from overseas.”

Mr Kalisch said “one breach … did actually get through via a third party … and [we] believe that we’ve plugged that gap.”

When asked if the hacks were a deliberate attempt to sabotage the census, Mr Kalisch replied: “We believe so.”

“The online census form was subject to four denial of service attacks yesterday,” he explained.

“The first three caused minor disruption, but more than 2 million forms were successfully submitted and safely stored.”

Mr Kalisch said the site was taken down just after 7:30pm after the fourth attack as a precaution to “ensure the integrity of the data”.

“The Australian Signals Directorate are investigating, but they did note that it was very difficult to source the attack.

“Steps have been taken during the night to remedy these issues and I can certainly reassure Australians that the data they provided is safe.”

Shadow Assistant Treasurer Andrew Leigh is furious the government failed to properly explain its decision to take the national survey online.

“If you can’t get the census right how can you govern the country,” he told ABC radio.

User fury

People were made all the more furious when the ABS refused to admit there was a problem for several hours, since the site dropped out completely at about 7.30pm.

It wasn’t until 11pm that the ABS acknowledged that their website would not be restored until Wednesday morning at the earliest.

ABS & Census website are unavailable. The service won't be restored tonight. We will update you in AM. We apologise for the inconvenience.

— Australian Bureau of Statistics (@ABSStats) August 9, 2016

To make things worse, many people were unaware that the actual due date for online forms is September 23 and they won’t face a fine before then.

A tweet from July revealed the ABS had expected a maximum of 500,000 Australians to submit forms every hour – a number many suggested was way off the mark.

Once the website went up again, this message told users to wait.

The nation’s first predominantly online Census was shrouded in controversy and complaints way before it was time to fill out the questionnaire – with changes to data retention triggering privacy concerns.

Politicians including Nick Xenophon, Jacqui Lambie, Scott Ludlam and Sarah Hanson-Young all announced they would boycott the changes by refusing to add their names and addresses to the form.

But protestors and believers alike were disappointed to find the ABS site unable to load from around dinner time, presumably when the bulk of Australia was attempting to access the form.

– Wrote the questions? Yep
– Organised big ad campaign? Yep
– Sent letters? Yep
– Tested the website works? Nah she'll be right #CensusFail

— シ Ed Gex (@EdDJGex) August 9, 2016

‘De-Nile isn’t just a river in Egypt’

Thousands of angry Twitter users congregated under the hashtag #CensusFail, which, created months ago, became a self-fulfilling prophecy.

Not making things better was the ABS Twitter account, whose official line was that the website was “running smoothly as expected”, even as thousands of complaints poured in.

@Ross_Greenwood why are you telling more people to log on? Put out a statement about the crash ! #censusfail

— jimmy jay (@mcjimmyjay) August 9, 2016

Curiously, the ABS had tweeted in July that its website was prepared to accept up to one million forms per hour – “twice the amount” they expected.

But with 65 per cent of households expected to complete the form online, the ABS was likely to have at least one million people attempting it between 7pm and 9pm.

So why do you hold "Census NIGHT" for a population of 20M+? 5pm-9pm = 4 hours. 20M/4 ~= 5M/hr. Who advised 500k/hr?

— John Painter (@johntpainter) August 9, 2016

Census conspiracy

Earlier in the evening, a number of users questioned why two Census hashtags showed up as “trending” on Twitter, but #CensusFail did not.

The top trending topic was #MyCensus, paid for by Census Australia.

Others pointed out the hashtag #CensusFail was not ‘auto-completing’, or filling itself in when you begin to type, as highly-populated hashtags normally do.

Every tweet in my timeline has #Censusfail tag. How can it not be trending on @twitter? Censorship? #auspol #census2016

— 💧Mike Wayville (@MikeWayville) August 9, 2016

Hmm #CensusFail isn't trending… wonder why.

— Wolf, guess what my username elsewhere is 🙂 (@wolfcat) August 9, 2016

#CensusFail finally auto completing on Twitter… Should've shown up hours ago… Hmmm

— David Nimmo (@DavidNimmo) August 9, 2016

Late on Tuesday night, #CensusFail became the top trending topic on Twitter worldwide.

https://twitter.com/TopTrendWW/status/762983398855970816

“Even if we want to make a difference we CAN’T!” complained one user.

Others dared the ABS to try and enforce the $180 per day fine, unaware of the September due date.

Prime Minister Malcolm Turnbull will probably regret this smug tweet he sent out around the time of the crash, claiming the Census was “v[ery] easy to do”.

We filled in the @ABSCensus tonight online – v easy to do. And so important for planning better Govt services & investment for the future

— Malcolm Turnbull (@TurnbullMalcolm) August 9, 2016

While many users appeared frustrated and angry, others pointed out the irony of the situation.

Privacy has been a heated topic in the lead-up to the Census, with many concerned the mountains of data submitted could be misused or end up in the wrong hands.

“Remember when we thought the government was competent enough to spy on us? Oh, so naive!” joked journalist Jen Dudley-Nicholson.

Remember when we thought the government was competent enough to spy on us? Oh, so naive! #CensusFail

— Jen Dudley-Nicholson (@jendudley) August 9, 2016

Maybe this is why calls to @ABSCensus are going unanswered… #CensusFail pic.twitter.com/2LgUNrWjWX

— Mackenzie Coonan (@mackenzieravn) August 9, 2016

Others were just happy to see all the #CensusFail jokes.

“Well at least twitter is pumping tonight. Feels a little like Twitter about 4/5 years ago,” wrote one user.

“Look #CensusFail is not as much fun as spill but it’ll do,” wrote another.

Fortunately for those who didn’t manage to complete the online form – or those whose paper form didn’t arrive in time – the ABS has given themselves until September to work everything out.

System architecture design at ABS. #censusfail pic.twitter.com/3QkJmCg6By

— Richard Tuffin (@RichardTuffin) August 9, 2016

https://twitter.com/PaulCunningham/status/762971824376336385

https://twitter.com/DavidCampbell73/status/762956461643141120

Breaking news. We have an image of #census2016 datacenter from moments ago. #censusfail pic.twitter.com/tqB5T48gs5

— Colby Swandale (@oceanicpanda) August 9, 2016

Who is keeping stats on #CensusFail tweets? #Sooometa

— James Bennett (@James_L_Bennett) August 9, 2016

Well at least @twitter is pumping tonight. Feels a little like Twitter about 4/5 years ago. #census2016 #CensusFail

— Rudolfo (@TheRealRudolfo) August 9, 2016