The Adoption Board has suspended applications to adopt children from Ethiopia and Rwanda after an examination of the two countries' laws turned up "important legal issues" requiring further examination.
The board decided to suspend the granting of declarations of eligibility and suitability for adopting from the two African countries until this examination was completed.
Kiernan Gildea, registrar of the Adoption Board, said the decision was a precautionary measure taken to protect the adoption process.
Couples intending to adopt from the two countries may continue to be assessed, but those already certified as eligible to adopt are being advised not to proceed with their adoption "until further notice".
Last August the board suspended applications to adopt children from Guatemala following concerns about adoption procedures and child-trafficking.
Minister for Children Brendan Smith described the decision to suspend applications to adopt from Ethiopia and Rwanda as appropriate in the circumstances and promised the issue would be dealt with quickly.
"The Adoption Board must make decisions in line with its assessment of the situation and its statutory responsibilities, to ensure that all activities are undertaken with the best interests of the child as a paramount consideration," he said, speaking at the annual conference of the International Adoption Association in Dublin on Saturday.
The issue is expected to be discussed at a meeting of the board today. Mr Smith promised that legislation to ratify the Hague Convention on inter-country adoptions would be published by the end of the year. The convention - which Ireland signed a decade ago but has not yet ratified - requires that inter-country adoptions take place only where it is in the best interests of the child and where no profit is made from the adoption process.
Speakers at the conference expressed frustration at the long delays in assessing couples. In some parts of the country, it can take up to five years to obtain a declaration of eligibility, and arranging an adoption from overseas can take several years on top of this. Mr Smith said he was conscious of the waiting times and added the HSE was reviewing inconsistencies in its services.
Prof Sheila Greene, director of the children's research centre in TCD, said most children who came to Ireland through inter-country adoption had demonstrated a "remarkable capacity" to achieve their potential once they were in a supportive home.