The Government will include all major mother-and-baby homes in an independent inquiry commission after the dramatic intervention of the Archbishop of Dublin, Diarmuid Martin.
r Martin said that only an independent inquiry led by a senior judicial figure could now provide the answers required from Ireland's escalating mother-and-baby home scandal.
The move will be confirmed once gardai have concluded preliminary investigations into claims that 796 babies were buried in a septic tank near the Tuam, Co Galway, home, which was run by the Bon Secours nuns.
Justice Minister Frances Fitzgerald has appointed two senior gardai and they will immediately begin work examining the Tuam mass grave claims.
A government source said last night that any wide-ranging commission of inquiry cannot interfere with garda investigations.
"But it is not a question of if there will be an inquiry – rather when, and how far will its remit go," the senior source said.
The operation of mother-and-baby homes from the 1920s to 1960s is regarded as the last of Ireland's church-linked scandals.
Vigils are to be held in Dublin and Galway in memory of the hundreds of children who died.
Justice for the Tuam Babies is planning a march from the Department of Children on Mespil Road to the Dail on Wednesday evening.
And Galway Pro-Choice will simultaneously hold a candle-light vigil at Eyre Square in Galway city centre.
Dr Martin warned that it was vital for modern Irish society that the matter be independently investigated, with issues such as secret adoptions and vaccine trials included.
"The only way we will come out of this particular period of our history is when the truth comes out," he said.
"The indications are that if something happened in Tuam, it probably happened in other mother-and-baby homes around the country.
"That is why I believe that we need a full-bodied investigation. There is no point in investigating just what happened in Tuam and then next year finding out more."
Dr Martin said the commission of inquiry needed to be powerful and independent.
"I would say it is very important that any commission set up has full judicial powers," he told RTE.
The planned government probe will be complicated by the fact the mother-and-baby homes issue involves secret vaccine trials; clandestine adoptions to wealthy Catholic families in the US; and infant mortality rates of 55pc, almost six times that for ordinary Irish maternity facilities.
Ground radar analysis has been conducted at Tuam and it identified "two anomalies". These may represent mass burial sites. The firm involved, TST, will refer its findings to gardai.
All material discovered by gardai will be referred to the State Forensic Anthropologist, Dr Lorraine Buckley, for dating and analysis.