The Court of Appeal has upheld a decision that two children, whose Irish father refused to allow them go back to their mother in France over the mandatory wearing of masks in French schools, must be returned home.

The court heard that the two primary school children were born in France, where they normally reside, to an Irish father and a French mother.

The two boys and their parents cannot be named for legal reasons.

The father returned to Ireland after the couple separated.

During a visit to Ireland last year, he decided he would not return the children to their mother due to rules in France requiring children over the age of six to wear facemasks at school.

While he did not want them to remain in Ireland permanently, the man argued that requirement to wear masks would adversely affect one of his sons, and would result in him suffering anxiety and distress.

Their mother, through the French courts, made an application under the International Convention on the Civil Aspects of International Abduction commonly known as the Hague Convention.

In a judgment earlier this year Ms Justice Mary Rose Gearty in the High Court rejected the father's claims and ruled that the children were wrongfully detained and should be returned to France.

That decision was appealed by the father, who said he was seeking a stay on the order until the facemask order in France had been lifted.

In its judgment today, the three judge Court of Appeal, comprised of Ms Justice Mary Faherty, Mr Justice Maurice Collins and Ms Justice Teresa Pilkington, dismissed all grounds of the father's appeal.

Giving the court's decision, Mr Justice Collins said that the evidence before the court fell very significantly short of establishing any grave risk or harm to the one of the children.

There was no plausible or meaningful evidence that the requirement to wear a facemask at school will have any adverse impact on the child, the judge said.

He added that it was not in dispute the proof required to make an order for the children's return under Article 12 of the Hague Convention had been satisfied.