Tens of thousands of Australians were unable to fill out their forms on census night this year when the website was targeted in a number of cyber attacks, which prompted the Australian Bureau of Statistics, or ABS, to shut it down for almost two days.
No data was lost but the estimated additional cost as a result of the shut-down was $30 million.
Speaking on Melbourne's 3AW radio station, Malcolm Turnbull has let slip details of a confidential agreement between the government and software giant, IBM.
He says IBM has agreed to cover the extra costs to the federal government as compensation for its role in the bungle.
"Overwhelmingly, the failure was IBM's. They've acknowledged that, they've paid up, they've accepted the blame and they should have. They were being paid big money to deliver a particular service and they failed."
He's confirmed there have been what he called "personnel changes" at IBM as a result.
But despite saying "heads would roll" at the Australian Bureau of Statistics when he first responded to the blunder, there haven't been any government staff sacked since the incident.
"There has been criticism of the ABS, they should have supervised the contract better, there's no doubt about that.
The important thing is to make sure the lessons are learned and the Australian people get a better service from the government."
Two inquiries were launched into the 2016 census to try to work out exactly what went wrong.
A Labor-dominated senate committee has reported back to say census implementation was the primary responsibility of the government.
Opposition Leader Bill Shorten says the government should take responsibility for its own mistakes.
"When does this government ever take responsibility for their own mistakes? I think that the buck stops with ministerial government and it doesn't just stop in terms of the ABS and ministers responsible for that. They've had three years to prepare for the census. They had one job and they couldn't do that properly."
Another report was handed down late yesterday by the Prime Minister's own special adviser on cyber-security, Alastair MacGibbon.
He said the census failure only added to what he called a "a roll call of sub-optimal online outcomes", which suggest the government's capacity to deliver digital services is failing.
Mr MacGibbon made a range of recommendations including a "cyber boot camp" for senior government officials to help educate them on the fundamentals of cyber-security.