The Taoiseach pledged that there would be no let-up in the search for the bodies of the so-called disappeared.

"We will continue to ensure that the Garda follow up this matter as long as there is evidence. I give that commitment to the House," said Mr Ahern. "We are keeping in touch with the families in as far as that is in our domain."

Honest intermediaries, he added, had worked very hard and diligently in trying to pinpoint the locations and all had acted in good faith. "Regrettably, the information does not seem to be satisfactory."

Mr Austin Currie (FG, Dublin West) said: "The behaviour of the Provisional republican movement over recent days and, indeed, the past 25 years, on this subject, deserves to be entered in the annals of infamy. I notice its representative in this House, as usual, is not here when this subject and others similar to it are raised."

The trauma of the relatives was indescribable, he added. "I have spoken to some of them. Injury is added to insult. It really is intolerable and we in this House and in this country have a right to be utterly angry at what these people are doing."

Later, the Minister for Justice, Mr O'Donoghue, told the House that work was ongoing by gardai at each of the six locations. "Where possible, the Garda search operations commenced at the point identified as the most likely point where remains would be located. The search areas in these instances have since been extended.

"Gardai have obtained the services of engineers where this is necessary, and the technical expertise from the Garda Technical Bureau is on hand at each location. Specialist radar equipment has been used to assist in the location of the remains. All resources required to complete this operation successfully are being utilised."

Mr O'Donoghue said that the level of success in locating the remains of the disappeared was dependent on the information which had been made available. "While there is no reason to doubt that everyone participating in this process is acting in good faith, we are also very well aware of the distress and trauma being caused to the families and relatives of these persons arising from the prolonged searches."

Mr Brendan Howlin (Labour, Wexford) said that either through callousness or carelessness the IRA had subjected the families of those killed to new levels of cruelty.

"I cannot believe that there are not people who know the precise location of the remains of these unfortunate victims. Even if the IRA, as an organisation, refuse to do anything more, there may be people who are no longer involved in the republican movement, people who deeply regret acts they many have been involved in decades ago, who have some information about the location of these bodies. I appeal to them to come forward, through intermediaries if necessary, to help end the agony of these families."

Mr O'Donoghue said that the topography of the six locations presented varying degrees of difficulty to the search teams involved.

The locations were: Ballydonnel Brook, Ballynultagh, Blessington, Co Wicklow, stated to contain the remains of Danny Mcllhone, missing since 1978; Kilmurray, Castleblayney, Co Monaghan, stated to contain the remains of Brian McKinney and John McClory, missing since 1978; Brogan, Carrickroe, Emyvale, Co Monaghan, stated to contain the remains of Columba McVeigh, missing since 1975; Templeton Beach car-park, Carlingford, Co Louth, stated to contain the remains of Jean McConville, missing since 1972; Oristown Bog, Kells, Co Meath, stated to contain the remains of Brendan Megraw, missing since 1978; Coghalstown, Wilkinstown, Navan, Co Meath, stated to contain the remains of Seamus Wright and Kevin McKee, missing since 1972.