Sinn Féin TD Brian Stanley has resigned from the party.
First elected to the Dáil in 2011 he has been involved with Sinn Féin for 40 years.
He said he would now remain a “Republican TD” outside the party.
The Laois TD said his decision follows on from a complaint that saw him “brought before an internal party inquiry.”
Mr Stanley described the inquiry process as flawed.
“”Considering what I have experienced and how Sinn Féin has dealt with this and other matters across the wider party in recent months, I can no longer have confidence in it”.
Mr Stanley’s departure from Sinn Féin comes just days after Kildare-South TD Patricia Ryan resigned from the party.
Ms Ryan said she has been unhappy for around 18 months and has been asking Sinn Féin to deal with issues, but said they were left to “fester”.
She said she had issues about being curtailed in what she would put up on Facebook, and with members being asked about questions for the leader in advance of meetings.