A test excavation has begun of the children's burial ground at the site of the former Sean Ross Abbey Mother and Baby Home in Tipperary.
The Mother and Baby Homes Commission confirmed that the excavation work began on Monday and is expected to last three weeks.
The announcement comes almost a month after a geophysical survey of the site was ordered by the Commission following a tip from a member of the public who approached the Commission with what is understood to be detailed information relating to the children's burial ground.
This is the only part of the campus that has been surveyed. Two other separate burial grounds, one for nuns and a further old burial ground were not examined on this occasion.
The examination of Sean Ross Abbey is the first time that any potential burial site outside Tuam has been excavated and comes more than three years after the first geophysical survey of the Tuam site.
Last week children's minister Katherine Zappone said that "initial testing" had been carried out at a nuns' burial plot on the grounds of the former Bessborough Mother and Baby Home but that no geophysical survey had yet been carried out at the site.
She said that this initial examination "may lead to more invasive test excavations" if necessary.
The Sisters of the Sacred Heart of Jesus and Mary, which ran the Sean Ross Abbey and Bessborough institutions, gave death registers it held for the homes to the HSE in 2011. They are now held by Tusla. Redacted versions of both were obtained by the Irish Examiner a number of years ago.
In the case of Sean Ross Abbey, the death register lists a total of 269 deaths between 1934 and 1967. However, research by campaigners indicates that as many as 800 children may have died there.
In the case of the Bessborough Mother and Baby Home, the register shows that 470 infants and 10 women died at the institution between 1934 and 1953.
A total of 273 deaths came in a six-year period between 1939 and 1944. However, the order reported 353 deaths to State inspectors in this period - a discrepancy which has yet to receive an explanation. It is unclear where all of the children listed on the register are buried.
Last year, an Irish Examiner investigation revealed that children from the Bessborough Mother and Baby Home and the former St Anne's Adoption Society, who died as late as 1990, are buried in unmarked graves in a Cork city cemetery.