Amid heated exchanges, Taoiseach Bertie Ahern refused to apportion blame for the ill-treatment of patients at Leas Cross nursing home in north Dublin.
Pressed by Fine Gael leader Enda Kenny, the Taoiseach said it would be "totally unfounded" to be critical of people who were now trying to rectify the issues involved.
"If Deputy Kenny is asking me, as he almost implies, that people were just totally negligent, that they didn't care what was happening to the elderly, and this was not of concern to them, or that they were incompetent . . .
"I do not believe that the senior people in the then health boards were responsible for that."
However Mr Ahern said it was a matter of "deep regret" that complaints and warnings were not given the attention they warranted.
He added that Prof Des O'Neill, who compiled the report, had not engaged in an exercise in blame, nor had he recommended disciplinary action.
"But it is a fact that some people involved have challenged his assessment. The report has been sent to the Garda and the Irish Medical Council for their consideration. There are matters which have to be examined."
Mr Kenny said preventing a repetition of such "institutional abuse" meant naming ministers and public servants who had to take responsibility and be accountable.
"Wrong was just not done; systems just did not fail; people did that wrong; and on your Government's watch, we have failed the elderly - and still fail the elderly."
It was not just about money, said Mr Kenny. Addressing the Government benches, he asked: "Is there anybody to blame? Is there anybody over there who will accept any modicum of responsibility or accountability for what we witnessed, for what we knew, for what we saw on our television screens, which was exposed by Deputy Fergus O'Dowd and Prime Time and others."
Mr Kenny said there was no accountability from the Health Service Executive.
Mr Ahern said that deficiencies in care were deeply upsetting to the families who died in Leas Cross and to many others.
"The Government understands their distress and we will lead the legislative actions and funding decisions to ensure that high standards of care are upheld in all nursing homes, both public and private in the State."
Earlier, Mr Kenny said that nobody had made a judgment on Leas Cross, just a "handy catch-all".
The position was that "opinions differed and patients died, all in the watch of this Government". Patients were mistreated, neglected and died.
"In China, they call that human rights abuse, but here we call it systems failure. Your Government is supposed to prevent this, but the departments came, saw, read, watched, knew and did nothing - and they are still doing nothing." Prof O'Neill had said in his report that the same thing could be happening elsewhere around the country.
"In fact, the only thing that has changed is time itself. On the evidence of the O'Neill report, what has happened here is that we have swapped institutional abuse of our young for institutional abuse of our aged, which is a national scandal."