Cllr Christy Burke has confirmed that he has resigned from Sinn Féin.
Mr Burke, who has served for 25 years as a party councillor for Dublin City Council, said he would better able to represent his supporters as an Independent.
He said he felt the support he got from the party during his campaign in the Dublin Central bye-election was 'watered down'.
Mr Burke said he also disagreed with the party line on a number of issues including voting against the council's budget estimates.
Dublin Sinn Féin chairperson Aengus Ó Snodaigh described the decision as disappointing, 'not least because it runs totally against the commitment which he made to the party and electorate only weeks ago when he sought and received the endorsement of a Sinn Féin election convention'.
