Sinn Féin president Gerry Adams has repeated his appeal for anyone with information on the "disappeared" to come forward to assist the agency that is expected to resume searches for the bodies this year.
Last year the Government approved proposals for a more co-ordinated and streamlined approach to locating the bodies of the "disappeared", based on information provided by IRA members who were directly involved in their killings.
An English forensic expert, who advised on where the bodies of the "disappeared" might be located, was retained by the cross-Border Independent Commission for the Location of Victims' Remains to continue his work.
Mr Adams said yesterday that the expert was retained after lobbying from Sinn Féin. During the summer Mr Adams disclosed that IRA "primary sources" - ie IRA members directly involved in the killings of the "disappeared" or their removal and secret burials - had assisted the expert.
The issue of the "disappeared" returned to prominence last year after DUP leader Ian Paisley revealed that a dying wish of the late human rights campaigner Msgr Denis Faul was that he use his influence in trying to find the bodies.
At the end of November, Dr Paisley met Vera McVeigh, the elderly mother of 17-year-old Columba McVeigh, who in 1975 was kidnapped, murdered and secretly buried by the IRA in a Monaghan bog. He appealed for information and said he would persist in his efforts to have the bodies located.
Mr Adams, also appealing for information, said yesterday that he expected that work to find the bodies would begin again this spring or summer.
"It is vitally important that those charged with this difficult task have all the information possible to make their efforts a success," he said.
"While I am mindful not to raise expectations by the families I know that the IRA has met with the forensic expert and that each site has been visited by the expert and the IRA, including individuals with primary knowledge. However, if there is any other information available which might help I am appealing for those with it to now bring it forward," he added.
In 1999, the IRA named nine people it killed and secretly buried. The bodies of four people, including Belfast woman Jean McConville, were recovered. A number of unsuccessful searches were conducted for the remaining five: Séamus Wright and Kevin McKee, from west Belfast, who disappeared in 1972 near Navan, Co Meath; Columba McVeigh, Co Tyrone, last seen in 1975 at Bragan, Co Monaghan; Brendan Megraw, west Belfast, missing since 1978; and Danny McIlhone, killed in the late 1970s or very early 1980s.
The list does not include Charlie Armstrong, aged 55 from south Armagh, who disappeared in 1981. While the IRA has denied involvement in his disappearance, security, political and local sources have claimed that IRA elements in south Armagh were responsible.