A secret mass children's grave has been found at an unwed mothers home in Ireland.

The bodies of 796 children have been discovered at a former religious home for unmarried mothers in Ireland, prompting calls for a full investigation.

The remains of foetuses and children, aged between 35 weeks and three years, were reportedly found in County Galway by the Commission of Investigation into Mother and Baby Homes, sparking questions about the treatment of single mothers and their children by the Catholic Church.

The Irish Mail reported the hundreds of deaths occurred from 1925 to 1961 at the St. Mary’s home, which was run by the Sisters of Bon Secours and financed by the Irish government.

While Sgt. Brian Whelan from Ireland’s national police force told CNN police are not investigating the matter, Charlie Flanagan, the Minister for Children and Youth Affairs, described the reports as “deeply disturbing”.

“[This is] a shocking reminder of a darker past in Ireland when our children were not cherished as they should have been,” he told the news outlet, adding the Government is currently devising the best course of action.

The head of the Tuam archdiocese, Archbishop Michael Neary, said in a statement he welcomes a formal investigation into the matter.

“I was greatly shocked, as we all were, to learn of the extent of the numbers of children buried in the graveyard in Tuam,” he said. “I can only begin to imagine the huge emotional wrench which the mothers suffered in giving up their babies for adoption or by witnessing their death, he told CNN.

“… This is a matter of great public concern which ought to be acted upon urgently.”

Curiously, the grim investigation was first ignited three years ago in 2014, when local historian Catherine Corless said she believed hundreds of children may be secretly buried on the site.

Speaking to The New York Times, Corless voiced frustration that she had been turned away and authorities failed to take her seriously until now.

“Nobody was listening locally or in authority, from the church or the state,” she told the publication.

“They said, ‘What’s the point?’ And that I shouldn’t view the past from today’s lenses.”

Corless says the children at the home lived in substandard conditions and some had been interred in the sewage treatment facilities.

A commission supported this suspicion, finding “significant quantities of human remains had been found in at least 17 of the 20 underground [sewage] chambers.”

Further tests are now being conducted and the commission has asked state authorities to take responsibility for the “appropriate treatment” of the remains.