A third politician has pulled out of an Oireachtas delegation to Colombia to oversee the trial of three Irishmen arrested on suspicion of collaborating with FARC guerillas.
Fine Gael senator Mr Paul Bradford said his decision was because "the trip had become the subject of partisan political squabbling".
A spokesperson for the families of the three said political manoeuvering had led to the withdrawals from what supposed to be a humanitarian trip.
Ms Caitriona Ruane said: "It is outrageous that some politicians have put party political interests above the safety and welfare of three Irish citizens."
She said the families were "deeply upset" by the developments but vowed the visit by political and legal observers would proceed.
In a separate development this evening, Ms Ruane said the families were taking legal advice following comments made by Ulster Unionist MLA Mr Dermot Nesbitt.
Nesbitt criticised the campaign which comprisesmembers of the men's families and human rights activists.
"This is an outrageous attempt to prejudice the men'strial and we are taking legal advice as to whether or not the statement is actionable," she said.
Earlier today, Mr Bradford became the third member of the Oireachtas group to pull out of the trip amid claims from a number of backbenchers in the Dáil that members of the House should not attend the trial.
Earlier, Fianna Fáil TD Mr Sean Curran announced his decision not to travel saying it was a personal one and that he had not come under pressure from his party.
However, a Fianna Fáil spokeswoman said Mr Curran's decision had been taken in the context of concerns expressed by a number of his colleagues .
Yesterday, Labour's Mr Joe Costello, Dublin Central TD, dramatically pulled out saying it was "a party decision" for him not to join the delegation.
A multi-party group had been asked to go to Bogota by supporters of the accused men.
The trip, organised by the Bring Them Home campaign - a group working for the release of Mr Niall Connolly, Mr Martin McCauley and Mr Jim Monaghan - is to be made up of three TDs and two Senators from various political parties.
Their mission is to oversee the men's trial which is due to begin on December 2nd.
Fianna Fáil TD Mr Sean Power today said serious questions had to be raised about the proposed trip. "I think parliamentarians deciding to go to monitor the trial is only giving comfort to Sinn Féin and should not happen," he said.
"Of course I am as keen as anyone else to see that a fair trial takes place". Mr Power said he believed it sufficient that the Republic's foreign affairs department would be monitoring the case.
He said most people he had spoken to were opposed to the group travelling to the trial. The matter will be discussed by party whips to see whether time can be given for a debate.
Ms Liz O'Donnell of the Progressive Democrats asked in the Dáil whether it was appropriate for deputies and senators to go to the trial of people accused of serious terrorist offences.
The TDs due to travel are Independent Mr Finian McGrath, Mr Sean Crowe of Sinn Féin. Fianna Fáil Senator Mary White will also make the journey to South America.
Bring The Home spokeswoman Ms Catriona Ruane said: "International attention is essential to ensure the safety of the three men. Our campaign is asking national and international observers to be at the trial".
Additional reporting PA