The agency in charge of the excavation of the former mother-and-baby institution in Tuam says work is due to start in the second half of June.
In 2016, investigators found what they described as "significant quantities of human remain" in underground chambers.
The Office of the Director of Authorised Intervention Tuam said the work would go ahead pending the appointment of the excavation contractor.
Office leader Daniel McSweeney says substantial and meaningful planning has gone into this unique and incredibly complex excavation.
The institution for unmarried mothers and their children was run by the Bon Secours Sisters and closed in 1961.
It came to international attention when local historian, Catherine Corless discovered that there were death certificates for 796 children and infants but no burial records.
The Irish government set up a Commission of Investigation into the network of mother-and-baby institutions, which later said the chambered structure containing the children's remains at Tuam was in a disused sewage tank.
The excavation team will aim to identify as many of the remains as possible.
Mr McSweeney said the exact start date would be confirmed in two weeks time
