They said the terms of reference for the Commission of Investigation were "utterly inadequate"
Sinn Féin TD Donnchadh Ó Laoghaire has called for a Truth Commission to be established to find out the facts about the Mother and Baby Homes.
Speaking this evening Mr Ó Laoghaire said "The revelations of recent weeks at Tuam, and subsequent reports regarding records and treatment of children, and their mothers, have shocked and angered Irish people.
"The suffering and the mistreatment of children and mothers in these institutions is a matter of national shame and, in many respects, there are many questions unanswered and those responsible have yet to be brought to account.
"The attempts to establish truth and address who was responsible for this dreadful part of our history has been piecemeal, flawed and utterly inadequate.
"The most recent action, the establishment of the Commission of Investigation in to Mother and Baby, under Judge Yvonne Murphy, was set up in the midst of widespread criticism that it's terms of reference were utterly inadequate.
"Those who suffered under the system but were not on the list of prescribed mother and baby homes were excluded.
"There has been a failure to recognise that, though the experiences in Mother and Baby Homes, Magdalene Laundaries, Industrial Schools, and other institutions are varied and different, that these are issues are linked."
He continued by saying "This was a regime, underpinned by an appalling attitude to women, particularly unmarried women and their children, which manifested itself across the institutions of the state.
"There are numerous examples of successful Truth Commissions internationally. We should take the best examples of these and apply the principles here in Ireland.
He finished saying "It should ensure that survivors groups are part of the process right from the beginning, that there is an advisory committee to the commission, and that hearings are in the manner which those victims and survivors are most comfortable with. There is also a need for international expertise."