Details of foreign adoptions of more Irish children may be contained in files held by the health boards and the Department of Education.
After the disclosures in recently discovered files that between 1,500 and 1,800 children were sent to the US between 1948 and 1973, the Minister of State for "child care, Mr Austin Currie, indicated yesterday that other details had yet to emerge.
He said some health boards also had records available to them which may shed further light on the practice of sending children abroad for adoption. The Department of Education records on children placed in industrial schools might also be of relevance, he added.
It is estimated that 70,000 children were detained in industrial schools between 1900 and 1970.
The Departments of Health and Foreign Affairs have emphasised that, because of legal difficulties, it will be some time before the hundreds of Irish children sent to the US for adoption from 1948 to 1973 can gain access to their files.
So-called "surrender" forms signed by the children's birth mothers in those files show that they consented to the adoptions taking place "inside or outside" the State.
Ms Nora Gibbons, the senior, social worker in charge of adoption advice for Barnardos, has said her "greatest fear is that these files will be buried again if the Government feels too swamped by possible legal problems".
She emphasised that other countries such as Britain had overcome such problems. Agencies like Barnardos had the necessary expertise to assist in this.
A spokeswoman for the Department of Health said it was still undecided who should have responsibility for co-ordinating the Government's response to the revelations about Irish children sent abroad for adoption.
She said the various Government Departments involved - Health, Education and Foreign Affairs - would have to consult and take legal advice, including discussions with the Attorney General.
Her understanding was that when women signed a form relinquishing all rights over their children and giving them up for adoption, they were guaranteed confidentiality.
She believed the pooling of information from Departments, the National Archives, the Adoption Board, the health boards and the religious institutions, along with the seeking of legal advice, might be a "long process".
A spokeswoman for the Department of Foreign Affairs said Irish legislation governed only Irish adoptions, so any legal opinion would also have to take into account US adoption law. She stressed that it was an "enormous issue" which would have to be treated with great sensitivity.
However, Ms Gibbons said the main priority was to set up a voluntary contact register. This would allow both adopted children and their birth families to indicate whether or not they wanted to re-establish contact. Such a register has existed in Britain since 1990.
She said Mr Currie supported such a register in the Republic, although he had said there were unspecified problems with including US-adopted children on it.