The grisly discovery of a baby’s body was made in bushes in Manor Park, Aldershot at 1.30pm on Friday, Hampshire Police said.
It is unclear how long the baby’s body has been there, said officials, and officers are appealing for the mother of the child to come forward.
Detective Superintendent Darren Rawlings said: “I am extremely concerned about the welfare of the mother of this baby and I want to make sure that she is getting the help and support she needs.
“I am making a direct appeal to her to get in touch with us.
“I know that this must be a very distressing time for you, but I want to make sure you are getting the right help and care.
“I understand that you are frightened but it is really important that you get the help you need.
“Our priority right now is to ensure that you get the care and any medical attention that you need.”
It is not yet known how old the baby is, nor its gender.
Mr Rawlings added: “If anyone has a friend or family member who they have concerns about, I would stress our immediate priority is to ensure the well-being and safety of this baby’s mother, so please contact us.
“I would also appeal to any healthcare workers who may have some information that may help us to get in touch.”
Anyone with information about the incident is asked to call police on 101.