Labour party chief whip Emmet Stagg has confirmed that he wrote a letter to a constituent in which he criticised recent changes made to the One-Parent Family Payment.
In an email Mr Stagg describes the changes as "a bad decision" and said he will continue to press for their reversal.
The Kildare TD said he "fails to see how cutting the income of the very ones who are making a real effort to improve the lot of their family and themselves helps in some way to get out of a poverty trap".
He said the cut "clearly has the opposite effect".
When contacted by RTÉ news Mr Stagg said he is aware that the letter has made it into the public domain, and he has no problem with this. He said he stands over his remarks and does not regret making them.
A copy of the email was tweeted by the Fianna Fáil TD Colm Keaveney who accused Mr Stagg of "appalling duplicity".
About 30,000 families across the country received their final One-Parent Family Payment last month.
They were moved to different payments, mainly to the newly-introduced Job Seekers Transitional Allowance or to Job Seekers Allowance, because their youngest child has reached the age of seven.
The Government has acknowledged that at least 4,000 of the 30,000 parents in part-time work will suffer an income loss as a result of the changes.