Gardaí are hoping that items of clothing on the dead infant discovered in a shallow grave in north Mayo on Sunday will help them to identify the baby.
Door-to-door inquiries were continuing yesterday in the Carrowtigue area of Erris to determine the identity of the woman whose dead baby was found in a black bin liner.
Chief Supt Tony McNamara repeated his appeal to the mother to come forward and assured her that she would be treated with the greatest sympathy.
He added: "We are perplexed that the mother has not come forward. We do understand she may be frightened to come forward. But I would assure her again, she will be treated with courtesy, consideration and compassion.
"We feel somebody else knows about the matter as well and because of misguided loyalty to her, they feel they do not want to say anything.
"But they are not doing her any service.
"It would be far better for them to come forward and they would be doing her a greater service."
The infant, discovered by local youngsters in the townland of Kilgalligan on Sunday, was 7lbs in weight and had been born around the middle of last week.
The baby was born full term and death occurred shortly after birth, gardaí say.
The services of a female gynaecologist and a psychologist have been secured through the Health Services Executive, Western Region, to attend to the mother should she come forward.
"These professionals will travel to meet this woman in any location in absolute privacy and secrecy," Chief Supt McNamara said. "I can give the woman involved my personal assurance that she will be dealt with sensitively and with compassion."