The Irish opposition leader has called for any members of the Fianna Fail party who know where three on-the-run republicans are to tell police.
The three republicans have returned to the Irish Republic
Niall Connolly, Martin McCauley and James Monaghan were sentenced to 17 years in jail in Colombia last year.
They vanished in December 2004 while on bail and have now returned to Ireland.
Fine Gael leader Enda Kenny said Prime Minister Bertie Ahern should ask members of his own party what they know of the men's wherabouts.
Speaking on Wednesday night, Mr Kenny said: "Mr Ahern should immediately direct any members of his own parliamentary party to come forward with any information."
Fianna Fail Senator Mary White, who visited Colombia seven times during the trial of the three men, denied she knew where the men were.
"I know nothing about them. I travelled seven times as an observer to ensure human rights were being respected," she said.
"If Fine Gael is referring to me, I know nothing."
Earlier, the Republic's deputy prime minister said the three republicans were no friends of the peace process.
Tanaiste Mary Harney said no deal had been done with Sinn Fein or the IRA over the men's return to Ireland.
"It is important that the three persons involved and those who have expressed exultation at their return to this country should not underestimate the government's determination to explore all the options open to it to ensure that Ireland continues to play its full part in the fight against international terrorism," Ms Harney said.
Ms Harney said the Irish government would consider any request from the Colombian authorities for their extradition.
She confirmed that no formal request for extradition had been received. Colombian vice-president Francisco Santos wants the men extradited but said he did not rule out allowing them to serve their sentences in Ireland.
The men, who had been accused of being IRA members, were arrested in Bogota in August 2001.
They were found guilty of travelling on false passports, in June 2004, but were acquitted of training Revolutionary Armed Forces of Colombia (Farc) guerrillas.
That decision was reversed after an appeal by the Colombian attorney general and they were sentenced to 17-year terms.