"What we've seen is Australians commit millions of hours in good faith for filling out the census and then find out that the census has been so bungled that it can't even be processed", he said.
"The ABS applied an abundance of caution and took the precaution of closing down the online Census form to safeguard and to protect data already submitted, protect the system from further incidents, and minimize disruption on the Australian public of an unreliable service".
The Australian Privacy Commissioner has also opened an investigation into the ABS and its handling of the attack.
This assumption caused a mild, online panic from users about whether they would be slugged a $180 fine per day for not being able to meet the Census deadline on time. The decision to conduct the national survey online and to keep the information for four years before it was destroyed instead of the usual 18 months heightened privacy concerns this year.
"I can certainly reassure Australians the data they provided is safe", he said.
According to ABC, at least two million census forms have been submitted online before the Census website crashed.
"My first priority is to ensure that no personal information has been compromised as a result of these attacks", Pilgrim said.
He said the site was equipped to handle heavy traffic, but there was a spike in visitors so steep that a router overloaded and the website was closed as a precaution.
Wilshire and Hartzer
Of course, that begs the question - why was the ABS still tweeting up until 9pm and later that "Tonight's Census night".
"Following, and because of this, there was a hardware failure", Mr. McCormack said, saying the ABS took a very cautious approach in shutting down the site.
The ABS received 2.3 million Census forms before the website was taken down.
The debate about privacy concerns has been raised despite assurances from the government that security would not be compromised.
After several "denial of service" attacks from unidentified sources created to stop people submitting forms, key parts of the hardware failed.
While citizens have until September 23 to submit the online census form, they will be fined $180 per day beyond the August 9 deadline.
Alex Ward said the "census is driving me senseless", after trying to log on through three different web browsers, devices, and networks.
Labor Leader Bill Shorten called it "the worst-run census in Australian history", and shadow assistant treasurer Andrew Leigh called for Mr. McCormack's resignation.