A Dublin woman who lost her brother in the Bon Secours Mother and Baby home in Tuam says she found out about the discovery of bodies on social media.
A state inquiry into mother and baby homes in Co. Galway has confirmed 'significant quantities' of remains.
They were found in what's understood to be a septic tank type structure at the site of the former institution.
The remains found ranged from premature babies to children aged 3 years old.
The commission says remains were discovered in 17 out of 20 chambers of what could have been an intended sewage tank. It's not known if it was every used as such.
Radiocarbon dating of the remains suggest they date from the 1950s. The home in Tuam operated between 1925 and 1961.
Anna Corrigan lost one brother there and believes another was given for adoption in America. She says the commission should have told families first:
"There were tweets... that human remains had been found and photographs of the digger. I had to send these to Judge Murphy and say is this the correct way to inform family members of what's happening with their family."
In a statement, the Mother and Baby Home Commission of Investigation said: "The Commission is shocked by this discovery and is continuing its investigation into who was responsible for the disposal of human remains in this way.
"Meanwhile, the Commission has asked that the relevant State authorities take responsibility for the appropriate treatment of the remains."
A public helpline has been set up for anyone who may be affected, and can be reached at 01 6473118.