There was more than 21 thousand anonymous tip offs of suspected welfare fraud last year.
The figure is up from just under 1000 before the economic downturn but is down on the peak of 28 thousand in 2012.
It resulted in savings worth 505 million euro last year but that's 5 million euro below target.
Most reports related to people allegedly working while claiming benefits.
Others were allegations that lone parents were living with partners and that people living outside the jurisdiction were claming benefits.
However despite the high number of suspected cases only a minority resulted in welfare payments being stopped or reduced.
Twenty gardaí joined the Department of Social Protections special investigations unit for the first time last year, securing 68 million euro while the department made 83 million euro in recovered overpayments.
