Update - 9.53pm: Campaigners claim revelations about adoptions are "the tip of the iceberg".
The Coalition of Mother And Baby Home Survivors say successive governments have ignored their concerns about incorrectly registered adoptions.
Chairperson Paul Redmond says a full Garda investigation of all agencies is needed, saying: "This is just the tip of a very large iceberg of fraud, forgery, baby trafficking, child abduction and criminal activity by rogue Irish adoption agencies who have destroyed tens of thousands of innocent peoples' lives.
"In actual fact we need a proper dedicated Garda unit to go into all the adoption agencies, every single one of them.
"Some of them are still going and they need to get stuck in there and secure that paper work."
3.46pm: Tusla uncovers dozens of cases of people who may not know they are adopted
Dozens of people placed for adoption in St Patrick’s Guild may not know they are adopted.
The child and family agency, Tusla, has identified 126 cases where births were incorrectly registered between 1946 and 1969.
They are cases where the adoptive parents of the child were recorded as the birth parents without an adoption order.
Seventy-nine of the people affected may have no idea they were adopted.
An independent review has been ordered into the incorrect registration at St Patrick’s Guild.
Children's Minister Katherine Zappone says while the practice of incorrect registrations has been known about for many years, it has been "extremely difficult" to prove and identify individual cases due to the "deliberate failure of those involved to keep records".
Minister Zappone said: “This is a very serious and sensitive issue. People have the right to know of their true origins and, where we have clear evidence, I believe we have an obligation to tell the people affected.
"Some may know already, but for others it will be entirely new and very difficult information indeed.
"Tusla has developed a plan for making contact with people and for providing the right supports for them as they absorb this information."
Following the discovery, further investigations will be carried out to see if there is any evidence of incorrect registration in the records of other former adoption agencies.
As there are around 150,000 records, Minister Zappone says a "targeted sampling exercise" will be conducted first to see if a major trawl is necessary.
Anyone looking for information about the new information can contact a Tusla Freephone helpline, which is operating at 1800-805-665 between 10am and 4pm on weekdays.
St Patrick's Guild Adoption Society was established in 1910 by the Sisters of Charity, and ceased operations in 2014.