Fine Gael is to ask the Government to set out what action it has taken under the anti-terrorist laws introduced after the Omagh bombing and to explain why the perpetrators have not been brought to account.
The party's spokesman on Northern Ireland, Mr Brian Hayes, has published a Dail motion calling on the Government to give a "balance sheet account" of the effectiveness of the special new powers - Offences Against the State (Amendment) Act 1998 - voted through in emergency session in the Dail after the Omagh bombing.
The motion is to be debated on Tuesday and Wednesday.
Mr Hayes said: "It is time we broke the culture of silence. Two years after the atrocity the victims of the Omagh bombing and all of us who support the peace process want those responsible to be brought to justice. If information exists that could help in the securing of convictions against the Real IRA, such information should be made available to the authorities."
He said if Sinn Fein could not advise its supporters to give that information to the RUC, it should advise them to give it to either a Government official or the Garda. Mr Hayes said the motion called for the unequivocal support of all members of the Dail in giving vital information that may lead to the arrest and conviction of the perpetrators of the atrocity.
The motion states: "That Dail Eireann, mindful of the public outrage that followed the Omagh bomb atrocity in August 1998, a criminal act carried out by the Real IRA, and recognising the continuing anguish caused to the victims of this bombing by the failure to secure convictions thus far, calls on the Government to: set out what action, if any, has been taken on foot of the enactment of the Offences Against the State (Amendment) Act 1998, details what further measures are currently being considered, outlines what discussions have taken place between the British and Irish governments on this matter, and, recognising the excellent investigative work that is jointly taking place between An Garda Siochana and the RUC, further calls on all members of this House to support the call made by both prime ministers, for the public to assist both police forces with their ongoing inquiries through the giving of information which may help in apprehending those responsible for this crime."