The group, which operates a peer support network of 2,000 adopted people, natural mothers and other family members, complained that the Department of Children and Youth Affairs (DCYA) had not published the wording of substantial amendments to be tabled within days.

A briefing note sent to TDs and Senators last week indicated that a substantially altered version of the Adoption (Information and Tracing) Bill 2016 would proceed to committee stage in the Seanad.

In a statement, the ARA said it is “opposed to the legislation, both in its current and proposed form, in the strongest possible terms”.

It continued: “Anything less than unfettered access to birth certificates (which are already public records) and unredacted early life and adoption records is deeply discriminatory to adopted people and those born in Mother and Baby Homes and similar institutions who have grown up under the closed, secret system here in Ireland.

“Instead of making reparation for the pain and human suffering caused by a system of coercive, closed, secret adoption and/or fostering, the DCYA is treating people who were adopted or subject to informal care arrangements, as well as individuals born in institutions, with deep suspicion and punishing them for simply seeking access to information about themselves.”