TV3 has told Fine Gael to "bring it on" after Vincent Browne's former producer, now a senior Fine Gael strategist, accused the station and the presenter of bias during a debate on the Court of Appeal referendum.
But he and senior Fine Gael figures were incensed by the TV3 debate on September 26.
A TV3 spokeswoman confirmed: "There was indeed a complaint made by a FG spokesperson. The complaint was that the programme was not fair, unbiased and proportional.
However, TV3 has rejected the complaint after it reviewed the programme.
"We are satisfied that the programme was fair, balanced and impartial. We also consider it was a substantial contribution to national debate on the issue," TV3 told the Sunday Independent.
The station criticised Taoiseach Enda Kenny for failing to take up its invitation to take part in the debate on the Seanad Referendum.
"If FG were concerned about issues of fairness, balance and impartiality in the run-up to the Seanad referendum debate on TV3, they could have nominated their most senior person on behalf of the Government and/or FG to attend."
The station added that Fine Gael "was welcome" to take its complaint to the Broadcasting Authority of Ireland (BAI) if it was unhappy with TV3's response.