Groups representing the families of babies who died in mother-and-baby homes were not informed that remains have been found at one site.
Today's media coverage was the first time that many relatives were officially told there were remains at the site in Tuam.
Anna Corrigan's two brothers were born in the home - but a death certificate was only ever issued for one of them.
She says the Commission is being used to stop a formal investigation into her brother's disappearance
The sister of a child who died in a mother and baby home says families should be given the option of reclaiming their remains.
It is after confirmation that remains have been recovered from the former home in Tuam, some of which were only 35 foetal weeks old.
One of Anna Corrigan's two brothers died in the Tuam home, while no records exist of another, who may have been adopted abroad.
She says if her brothers are in the burial site in Tuam, they should be exhumed and put in her own family plot.
The chairperson of the Coalition of Mother and Baby home Survivors (CMABS) has said the bodies uncovered at the former mother-and-baby home in Tuam "is the tip of the iceberg" which they claim will "amount to at least 6,000 babies and children".
They also spoke of their shock at having to learn of the discovered bodies in the news.
Paul Redmond, chairperson of CMABS, said: "What is shocking is that once again we have to learn of this news via the media. The communications skills of the Minister and the Commission of Inquiry leave a lot to be desired when it comes to informing the Survivor Community of developments.
"Tuam must not be seen in isolation. There are over 227 confirmed deaths in the notorious Bethany Home in Dublin and recent research has revealed the names of over 200 babies and children buried in the Angel's Plot at Castlepollard mother-and-baby home ranging from a few hours old to over two years. There were also at least 77 confirmed stillbirths in Castlepollard above and beyond the 200 registered deaths.
"The worst is yet to come as details of the huge behemoths of Saint Patrick's, Bessboro and Sean Ross Abbey have yet to be revealed."
He urged the Government, Minister Zappone and the Inquiry to consider living survivors before any further excavations are carried out.
He said: "Our community is ageing and has been viciously cut in two by the current official policy of excluding many survivors from the Inquiry. Survivors need to be heard instead of ignored; consulted instead of insulted; treated with respect instead of learning the latest developments via the media."
It has emerged that the relatives of children who died at a mother-and-baby home in Tuam were not informed that remains had been recovered.
A woman whose brother died in the home says the only official confirmation that remains were found came through the media today.
Anna Corrigan lost one brother in Tuam, and believes another was given for adoption in America.
She says the Commission should have told families first, before announcing the recovery of human remains.
Ms Corrigan said: "There was tweets up on social media that human remains had been found, the digger is in, photographs of the digger.
"I had to send these to judge Murphy and say 'is this the correct way to actually inform family members of what's happened with their family?'."
There have been calls for other mother-and-baby homes to be included in an inquiry following the grim discovery of a significant amount of human remains in Tuam, .
Sinn Féin TD Donnchadh O'Laoghaire said today that he will ask the the judge heading the commission of investigation into Church-run mother-and-baby homes to extend the inquiry's remit.
The move comes after the shock revelation this morning that a large amount of human remains were were discovered at a Galway site excavated by the Mother and and Baby Homes Commission.
The commission says it is “shocked” by the discovery in Tuam.
“These remains involved a number of individuals with age-at-death ranges from approximately 35 foetal weeks to 2-3 years,” the body said.
Deputy O'Laoghaire said he would be pressing for the Oireachtas Committee on Children, which he is a member, to ask commission judge Yvonne Murphy to come before it.
It was an “extremely sad and shocking” discovery and an indictment of Ireland at the time and it was now a national scandal, added the Cork South Central TD.
It was “vitally important” that the coroner for County Galway was now involved, he said.
"It is important because we need to establish the circumstances of the deaths of these children and if those children died in any manner of violent way and therefor if the coroner needs to contact the gardai.”
It was also "very disappointing" that many of the victims groups had not been contacted, he added, or made aware of the statement in advance.
“It is necessary to try and identify as many as of the remains as possible and the whereabouts of their passing.”
Contact would need to be made with families then where identities were established, added the Sinn Fein TD.
“There should be some sensitive way of memoralising the victims and giving them the dignity that they deserve, which they did not receive on their passing.
"I will be requesting that the Oireachtas Committee on Children and Youth Affairs invites Judge Yvonne Murphy before it to discuss these revelations, to discuss the terms and reference for the commission and the possibility that Tuam may not be an exception.”
He said he personally had been contacted by people who claimed there were other sites that must be investigated.
"There are fears that not all of these sites, even in Tuam, were investigated.
"If there is any evidence to say that there is any evidence that exists on the sites of any of the other mother and baby homes, they also need to be investigated and I want to discuss that with Judge Murphy.”
The TD also said that the grim discovery now suggested that this had been a “cover up”.
“It certainly has that appearance. It seems difficult to imagine that this was carried out in any legal way.”
"Significant quantities" of human remains have been discovered on the site of the Tuam mother-and-baby home,.
The Commission to Inquire into Mother and Baby Homes have said they are "shocked" by the discovery and is continuing its investigation into who was responsible for the disposal of human remains in this way.
The examination of the site uncovered two large underground structures. One of these was divided into 20 chambers.
Significant quantities of human remains have been discovered in at least 17 of the 20 underground chambers which were examined. A small number of remains were recovered for the purpose of analysis.
These remains involved a number of individuals with age-at-death ranges from approximately 35 foetal weeks to 2-3 years. The Coroner has been informed.
Radiocarbon dating of the samples recovered suggest that the remains date from the timeframe relevant to the operation of the Mother and Baby Home (the Mother and Baby Home operated from 1925 to 1961.
The Commission has not yet determined what the purpose of this structure was but it appears to be related to the treatment/containment of sewage and/or waste water. The Commission has also not yet determined if it was ever used for this purpose.
The discovery raises further questions as to when the Commission will start examining other Mother and Baby Home sites for remains.
Last month, it informed the Irish Examiner that there has been “no decision” to carry out excavations on the site of any other mother and baby home other than Tuam — despite the HSE confirming as far back as 2012 that there had been a higher infant death rate in Bessborough in Cork.
An Irish Examiner investigation in 2015 revealed that the HSE informed the Department of Health and the Department of Children and Youth Affairs of a “shocking” infant mortality rate at Bessborough in 2012.
The unpublished report also expressed concerns that deaths may have been falsified at Bessborough so that children could be “brokered into clandestine adoption arrangements”.
The investigation revealed that the HSE had also reported concerns in 2012 that up to 1,000 children may have been “trafficked” to the US from the Tuam mother and baby home in “a scandal that dwarfs other, more recent, issues within the Church and State”.
Senior HSE officials advised “that this goes all the way up to the minister” so “a fully fledged, fully resourced forensic investigation and State inquiry” could be launched. An inquiry was not launched by the Government until two years later.
Factual helplines about today's findings in Tuam:— Gavan Reilly (@gavreilly) March 3, 2017
Affected public can also directly contact HSE line:
1850 241 850
Minister for Children Katherine Zappone described today's revelations as “very sad and disturbing news”.
“It was not unexpected as there were claims about human remains on the site over the last number of years," she said.
“Up to now we had rumours. Now we have confirmation that the remains are there, and that they date back to the time of the Mother and Baby Home, which operated in Tuam from 1925 to 1961.”
Ms Zappone also stated: “Today is about remembering and respecting the dignity of children who live their short lives in this home. We will honour their memory and make sure we take the right actions now to treat their remains appropriately."
Zappone - options include leaving remains or reinterring them. Statement: pic.twitter.com/JfmDKgaD0X— Aoife Barry (@sweetoblivion26) March 3, 2017
Labour spokeperson for Children and Youth Affairs, Jan O'Sullivan TD, said: "I am deeply saddened and concerned to hear confirmation today of the recovery of human remains at the site of a former mother and baby home in Tuam in Co Galway.
"The brave women who lived at the home as well as their relatives who have come forward over the past number of years to tell their stories, and the painstaking research by local historian Catherine Corless, have helped to shed light on another dark chapter in Irish history.
"I continue to offer my support to the ongoing work of the Commission of Investigation into Mother and Baby Homes, which is due to release its final report next year, and hope it will be of some help to the former residents and their families."
.@KZapponeTD responding to the news now - confirms the remains are from the era of mother and baby home's operation, and not earlier— Gavan Reilly (@gavreilly) March 3, 2017
Could there be more than 800? "We don't know."— Gavan Reilly (@gavreilly) March 3, 2017
A dedicated telephone information line for factual information and a service for those who feel personally affected by the news on 01-6473118/01-6473232.