People who didn't receive their full disability allowance because they were living in residential care are to have the balance restored, according to the minister for social affairs.
It is part of the Government package of reforms announced in the last budget.
The full allowance is €185, but two-and-a-half thousand people who went into care homes before August 1999 only got half that amount every week.
"I think we presume that people in residential institutions have a different financial regime but in fact they have plenty of costs and responsibilities as well," said minister Seamus Brennan.
"This is correcting something that should have been done many, years ago."
Minister Brennan stated it was important to realise that it was not an ongoing problem
but something that just affects these particular 2,500 indivduals.