Sinn Féin leader Gerry Adams has said there is no culture of bullying in the party and it is unfair to members to suggest there is.
Mr Adams was responding to claims by a Limerick councillor who resigned from the party.
Lisa Marie Sheehy claimed that she was bullied and undermined.
In a statement, Ms Sheehy announced she was stepping down as a result of what she called "the alarming increase of intimidation" within the party, which she said amounted to nothing short of bullying.
Speaking on RTÉ Six One News, Ms Sheehy said she stood down because she was consistently undermined and bullied and could not take it anymore, saying it was affecting her work.
She said that she did not understand why she was "cut down" at every point. Ms Sheehy also said that the issue was not dealt with properly by the party when she "went to sort it out".
She is continuing as an Independent councillor for Limerick City and County Councils.
Mr Adams said the party carried out an investigation and did not find any evidence to support the claim.
Asked whether there was a pattern of councillors resigning from Sinn Féin, Mr Adams said "it happens in all parties".
Sinn Féin finance spokesperson Pearse Doherty earlier said Ms Sheehy's claims of bullying "could not be substantiated".
Speaking on RTÉ's Today with Sean O'Rourke, Mr Doherty said he was "disappointed" to hear of the resignation.
Mr Doherty described Cllr Sheehy as a "very hard working councillor who delivered for her community".
However, he said she was asked to provide her allegations in written form but she did not do that.
Mr Doherty said there was a preliminary inquiry where everyone was spoken to and he said it was shown that the claims could not be substantiated.
He said Sinn Féin would not tolerate bullying in the party.
He said if there was any evidence of bullying within the party, it has "robust procedures" including expulsion.