The body was discovered by a member of the public before 10am yesterday.
The scene, at Bell’s Beach at Balbriggan, Co. Dublin, was sealed off for a technical examination.
The remains have been taken to Temple Street Hospital.
A post mortem examination completed today, 16th December 2018, established that the child was a full term baby girl.
It was also determined at there was no foul play involved in the death of the child.
Gardaí are concerned for the wellbeing of the mother, who will require medical attention, and have made an impassioned plea her to come forward.
“I can assure you, you will be treated with the utmost of compassion and care and 100 per cent confidentiality,” Sergeant Fiona Savidge told a press conference this afternoon.
“I know you are a daughter, I know you are possibly a sister, a cousin. You may have a husband, a boyfriend, you may just have confided in a friend," she added.
Gardaí are appealing to the mother of the child to come forward and we are also appealing to anyone with information to contact Balbriggan Garda Station on 01 8020510.