Johannesburg: A South African court has approved an investigation into a case of two baby girls mistakenly switched at birth in a hospital in 2010 and given to different mothers who are now in disagreement over how to resolve the situation.

The Centre for Child Law, a South African group that promotes children's rights, says a court has appointed it to find out about the switch at a Boksburg hospital near Johannesburg, and to decide what would be in the children's best interests.

One of the mothers, who is single and unemployed, recently learnt about the mistake while trying to get child support. She wants her biological daughter to be placed in her care, and to return the other girl to her biological mother, according to court documents, but the second mother has refused.

"We have to do a comprehensive investigation regarding the circumstances of the swap, the children's current circumstances and what would be in the children's best interests in the long terms," Carina du Toit, a lawyer at the Centre for Child Law, said.

The children, now nearly four years old, were born at Tambo Memorial Hospital on August 2, 2010, but the mother who wants her biological daughter back only learnt about the swap recently when she and the father took paternity tests in a dispute over child support, Ms du Toit said in an April affidavit in a provincial court.

The results concluded that neither parent was biologically related to the girl who was in the mother's care and the father was not legally obliged to provide child support because the girl was not his daughter.

The mother approached the hospital, which acknowledged the unexplained swap and organised joint therapy sessions for the two mothers over several months ending in February.

However, the mother seeking to have her biological daughter returned to her "became unhappy with the process" and took her case to the children's court, according to court documents.

In her affidavit, Ms du Toit said she did not know the location of the biological fathers and that each child was with a caregiver who was not recognised by the law as the child's guardian. She said litigation "might be necessary and inevitable to remedy the tragic situation in which these children and mothers find themselves".

"There is a potential conflict of interests between what the biological mothers desire as an outcome and what may be in the best interests of the children."

AP