A row broke out between Fianna Fáil leader Micheál Martin and European election candidate Niall Blaney at a press conference in Dublin.
Mr Blaney accused the party leadership of not giving the "same support" to his campaign as it had done for other candidates.
Senator Niall Blaney is running with two other candidates- Senator Lisa Chambers and Barry Cowen TD - in the hotly contested Midlands-North-West constituency.
At the press conference, Mr Blaney said he was "looking for equal treatment" and said he had not yet had a TV opportunity during the campaign.
"Unfortunately I am not getting the support as other candidates. I am the only candidate of six that has not got a TV opportunity," he said.
Mr Blaney added: "That is not just about me, that it is about the people I represent in the border counties."
Micheál Martin rejected the criticism and said "I canvassed with Niall".
In an attempt to defuse the row, he said: "We will deal with the campaign after the press conference, I'm not getting into a public discussion on the logistics of a campaign at a press conference."
He added: "There is huge support going to all candidates from the party."
Fianna Fáil does not hold a European Parliament seat in the Midlands-North-West constituency.
The party is running two candidates in the Ireland South constituency Billy Kelleher MEP and Cynthia Ní Mhurchú.
In Dublin, its candidate is Barry Andrews MEP.
