Ireland will allow tens of thousands of adopted people access to their birth certificates for the first time under proposed legislation that some advocacy groups say could still deprive many of their identities.

International laws say all children should be able to establish their identity but adopted people in Ireland, many of whom were sent for adoption in secret by Catholic institutions, have no automatic right to their birth records or access to tracing services.

Successive governments had argued that a 1998 Supreme Court ruling prevented them from opening adoption files because it emphasized the mother's right to privacy. But Children's Minister James Reilly said on Monday that any adopted person should have a statutory right to apply for a birth certificate.