In a tweet sent from his own account, Donnelly said: “Just been told that I’ve been blocked from the SocDems twitter account. I mean that’s just childish.”
The Wicklow TD was a founding member of the party in July 2015, but left in September this year because the leadership team did not “function very well as a team.”
Social Democrats have replied to Donnelly’s tweet, stating that it is an error they are now looking into.
It reads: “Hey Stephen, our apologies…totally unintended, looking into what happened now but apologies for the confusion!”