An international authority on excavating human remains has advised the expert group investigating the infant remains buried beneath the former mother and baby home in Tuam.

The International Committee of the Red Cross, which has worked to recover and identify bodies from mass graves in conflicts across the globe, has been consulted by the expert group, as it nears the end of its technical examination of the site.

The charity is a leading expert on searching for, recovering, analysing, identifying, and managing large numbers of unidentified remains in varying states of preservation. Extraction and analysis of DNA are among the key issues the group is considering.

An update, published on the Department of Children's website last week, said that the group had also liaised with An Garda Siochana and the coroner for North Galway, who has a role in investigating sudden, suspicious or unnatural deaths. It has also liaised with the National Monuments Services and Forensic Science Ireland.

The Department's update provided no further information on the number of children that might be buried under the site of the former mother and baby home in Tuam.

The only information released to date is that the quantity of human remains is "significant" and that they belong to children aged from about 35 foetal weeks to three years.

However, local historian Catherine Corless, whose research led the Government to set up a Commission of Investigation into Mother and Baby Homes, has estimated that the remains of up to 800 babies could be buried there.

The matter of identifying the remains, and whether they should be excavated and re-interred elsewhere, has been one of the contentious and complex issues that followed their grim discovery during an excavation last March.

Some survivors of the home are pressing for a full excavation of the site, including Peter Mulryan, whose sister was listed as having died at the home of "a convulsion" aged 10 months.

As with all of the babies believed to be interred at the site, there is no burial record for Mr Mulryan's sister.

The Minister for Children and Youth Affairs, Katherine Zappone, appointed the expert group after an excavation ordered by the Commission of Investigation into mother and baby homes confirmed the existence of infant remains.

The latest bulletin was the second issued by the Minister, who has promised to publish monthly updates on the first Friday of every month.

The Minister also conveyed to the Commission of Investigation concerns raised with her about the proposed sale of the site of another mother and baby home at Bessborough in Cork.

The latest report comes as the UN Committee against Torture called on the Government to carry out an independent investigation into allegations of ill-treatment at all mother and baby homes, not just some.