The Minister for Health has indicated that politicians will be among those likely to face criticism in the Travers report on illegal nursing-home charges.
Ms Harney also gave the Dáil a revised estimate of up to 300,000 for the number of people eligible for repayment and compensation.
Describing the scheme as a "mammoth task" on an unprecedented scale, she said the need would be for "some outside expertise, perhaps even from outside the country, to help us with the task, because in other jurisdictions people have handled mass claims in the past, and they would have a good deal of experience".
She also insisted that people who were due money would not have to employ a solicitor.
Minister for Finance Brian Cowen said later that an estimated 275,000 people had gone through the system, according to figures he had seen, but they were working off "guesstimates".
"What amount will be due to any of those people is a matter still to be decided based on legal advice and is being considered by the Government," he added.
Figures for the cost of repayment have varied from €500 million to €2 billion.
Ms Harney came under attack from the opposition for guillotining the Second Stage debate of the Health (Amendment) Bill to allow charges to again be deducted from long-stay patients' pensions. This follows the Supreme Court judgment that long-term residents of public nursing homes had been illegally charged.
Labour leader Pat Rabbitte called on the Minister to explain her remarks about "systemic maladministration" in the Department of Health.
Ms Harney said maladministration did not just affect public officials.
The Minister, who will receive the report today, said when the charges were levied "we thought it was on the basis of good faith, and that no one knew that what we were doing was wrong. That was not the case.
"It became very clear over recent weeks that it had been known for a considerable time that we were acting illegally."
She promised she would publish the report on Tuesday.
Later in the debate Minister of State Tim O'Malley, who attended a meeting of key officials about the issue in December 2003, said: "I presumed legal advice would be obtained, and this is what I told anyone who asked me about the matter".
On the repayment scheme, Ms Harney said: "We want to do things as quickly as possible, but this is a mammoth task involving more than 200,000 people, perhaps as many as 300,000, so the logistical issues as to how this might be handled must also be examined".
The Government was "working on a scheme of repayments that will be efficient, user-friendly and as automatic as possible".
She said: "Persons who were being charged need not employ a solicitor to get what they are owed".
The intention was "where we can identify people, we will pay them their monies. It will not be a question of making applications.
"In the case of deceased persons, somebody will have to prove that they were the representative of that person.
"For those who are alive but of unsound mind, the statute of limitations cannot be applied to people who are of unsound mind."
