The Department of Social Protection has launched investigations into 3,300 cases of suspected welfare fraud this year.
Forty-five people have also been convicted in court this year.
These new figures from the Department of Social Protection relate to the first six months of this year.
During that period, the department received more than 7,300 reports of suspected social-welfare fraud.
After these allegations were filtered, 3,260 were referred for investigation.
Forty-one cases have been referred to the Chief State Solicitors Office.
A separate 53 criminal cases were finalised in court, 45 of whom were convicted, with two jailed.
Sinn Féin's social-protection spokesman, John Brady, said: "The figures that have been revealed show a significant decline in numbers, both reported, sent on for investigation, and indeed, where people have been found guilty."
The department has also recovered €39.2m in overpayments, or fraudulently obtained welfare payments, in the same period.