The Adoption Authority has refused to recognise or register more than a dozen Mexican-born children adopted by Irish families, the High Court has heard.

The refusal comes because the children's placements do not comply with provisions of the international agreement on inter-country adoptions.

The Hague Convention on the Protection of Children became law in Ireland when the Adoption Act was formally ratified on 1 November 2010.

One of the families affected, who cannot be identified, has brought a High Court challenge against the Adoption Authority of Ireland and the State over the refusal to recognise the adoption.

They claim they cannot fully comply with a requirement under the convention to have the adoption recognised because their daughter was placed with them prior to Ireland's ratification of the Hague Convention.

They claim that requirement is unlawful and the authorities' refusal breaches their constitutional rights to protection of the family, and their rights under the European Convention on Human Rights.

The couple have asked the High Court to quash the Adoption Authority's decision of 28 February last to refuse to recognise and register the valid Mexican adoption of the child by her parents.

They are also seeking orders recognising their child as an Irish citizen and the couple as her adoptive parents.

They are also seeking various declarations including that sections of the 2010 Adoption Act which deal with the recognition and registration of foreign adoptions Ireland fall short of what is intended in the Act and incompatible with their rights under Articles 40 and 42 of the Constitution.

The couple adopted a Mexican girl shortly after she was born in July 2010. After going through various steps their valid adoption was eventually put into effect by a Mexican Court in March 2011.

They were then provided with the relevant documentation they believed they required to have the adoption recognised in Ireland.

Following their return home from Mexico, they applied to the Adoption Authority to have the adoption recognised. A protracted correspondence then followed.

The couple said the authority informed them it did not have the statutory power to recognise or register the adoption.

As a result their child cannot get a passport or be recognised as an Irish citizen, and the couple are not recognised as her guardians.

In a final letter from the authority the couple were told that it intends to notify the HSE of their inability to recognise the adoption so that the HSE is aware of the issues arising with their inter-country adoption.

The family said this is "a chilling statement".

In order to have their daughter's adoption recognised they were asked by the authority to provide a certificate - known as an Article 23 certificate - as proof for the registration of the adoption.

Under the convention the certificate is generated following agreement between the authorities in both the child's country of origin and the prospective parents' country prior to the child's placement.

However the couple say that request is impossible to fulfil because on the date of their child's placement with her adoptive parents in July 2010, the Hague Convention did not have force of law in Ireland.

The couple say that they had a legitimate expectation that their adoption would be recognised. They got approval from the relevant authorities here, including the HSE, to be allowed adopt and went through the same process other couples who have adopted a child in Mexico have undertaken.

Prior to the placement they were in contact with the authority. However the couple say it never informed them in an effective manner about the impact that the change in Irish law on 1 November 2010 would have for the registration of adoptions still in progress in countries that are signatories to the Hague Convention.

In an affidavit to the court, one of the parents said that the authority will not recognise a total of 19 adoptions by Irish families from Mexico.

A letter from the Mexican Embassy on the situation displayed to the court referred to the children as victims and urged that they remain in Ireland and that a solution be found.

The well-being of the children must prevail over all other concerns, the letter adds.

Permission to bring the action was granted, on an ex-parte (one side only) basis, by Mr Justice Michael Peart. The case returns to court in June.