Tusla says records for the mother-and-baby homes in Tuam in Galway, as well Bessborough in Cork, and St Patrick's in Dublin, have been transferred to the agency.
The indepedent child and family agency has confirmed it can make these available to the inter-departmental inquiry being established by the Minister for Children Charlie Flanagan.
Tusla says that 9 registers from 1921 to 1961, along with quarterly returns from county councils dating back to 1919, are in its possession.
Chief executive of Tusla, Gordon Jeyes, has said they have no problem in making these available to the interdepartmental review group set up by the Government.
However, he stressed the data is private and is being held in trust on behalf of individuals.
He added that the agency plans to digitise the registers but they will remain confidential and will only be made available to the inquiry or the individuals concerned.
Earlier, Education Minister Ruairi Quinn backed a call for an independent inquiry but said the full facts should be established first before an investigation is established.
