Minister for Social Protection Joan Burton has said around €10m has been recovered through new data-matching measures carried out with the Revenue Commissioners to help identify fraudulent social welfare claims.
The Department of Social Protection has been carrying out data-matching with Government departments and other agencies to identify potential fraud cases.
In one case, a man who was in receipt of Jobseeker's Allowance was found to have close to €400,000 on deposit with a financial institution, which had not been declared.
The man was convicted, fined €2,500 and received a four-month suspended prison sentence.
He has since paid back €30,000 in benefits in full.
Speaking on RTÉ's Morning Ireland, Minister Burton said Revenue would have identified people who had high levels of interest on investment earnings, and these were then matched against social welfare records.
She said spending in her department was always under fierce scrutiny, and it was important to make sure money goes to the people who need it.
Information was provided by Revenue to the department on persons who had been paid interest on investments, and this data was matched with departmental records.
The department's Special Investigation Unit investigated a number of cases in the Jobseeker's Allowance, One-Family Parent and Disability Allowance schemes. So far, 941 case investigations have now been concluded.
The department said these investigations have resulted in overpayments and "disallowance" of social welfare payments to the value of €25.7m.
This figure includes the amount of money that would have been paid out over the course of the year of the claim if the payment had not been stopped.
A number of cases detected during the project have or will be brought before the courts.