Police in Greece are seeking international help to identify a four-year-old girl found in a Roma settlement, who is believed to have been abducted at birth.

Vassilis Halatsis, the police director of Thessaly, said on Friday that the girl had been found living with a couple whose features were "totally different", and DNA tests had shown no relation between them.

"So far we do not have a declared disappearance of a child of this age in Greece," he said. "We will request assistance from the other European countries."

The police found the girl during a search for drugs and weapons in the settlement in the town of Farsala, central Greece, on Wednesday.

A 39-year-old man and his 40-year-old wife gave conflicting stories on how they found the girl, leading police to believe she was taken from her real parents in 2009.

"The girl might have been abducted from a hospital, or given up by an unmarried mother," Halatsis said.

The Roma couple have been arrested and charged with abducting a minor. Their lawyer, Marietta Palavra, said they took her out of charity, through an intermediary, while she was just days old from a foreign stranger who said she could not support her daughter.

"It doesn't make her a kidnapper," she said of the mother, adding: "The couple loved the girl as if she were their own."

Panayiotis Pardalis, a spokesman for the charity which is caring for the girl, said: 'It was obvious that she was not a Roma girl.

"She was afraid and under some psychological pressure when she arrived. Colleagues have been trying to communicate with her but are struggling."