Independent TD Mick Wallace has been fined €7,000 for failing to pay pension contributions for his workers into their pension fund.
Mr Wallace pleaded guilty to five charges of deducting pension contributions and failing to pay them in the Construction Workers Pension Scheme between January and May 2008.
He was fined €1,000 for each of the first four charges and €3,000 for the final count.
Judge James Paul McDonnell said the courts take a very serious view of such offences.
Outside court, Mr Wallace said it was a very serious matter but all the money had now been paid over.