Bright would not answer other questions about the ethnicity or state the child was found in as it is too early in the investigation.
"It's really really early in the investigation."
Hunt for mother after baby found dead
A member of the public found the baby while walking through the reserve on Mona Ave in Mangere Bridge about 8.30am.
The reserve has been cordoned off and a police specialist search unit is at the scene. McDonald's wrappers lay strewn on the ground and there is smashed glass in the carpark.
Equator Sausoo, 30, who works next door, picked flowers on his lunch break and said a prayer as he lay them down at the park.
He said he was particularly emotional as he was a father of five.
"It just shocked me so I came down to say a little prayer."
Uaa Meti works at the door factory next to the park. "It just sends chills down the spine, especially being so close to home."
A local resident, who gave his name only as Aaron, was horrified when he learned what had happened.
"That's terrible. That's f***ing disgusting. Especially a little baby. I'm sorry to hear that."
Mangere MP Su'a William Sio said the discovery was "very, very sad".
"Jeepers, that's devastating. Devastating for the baby and for the mother."
He suspected the baby had been abandoned by a young mother who had no support.
"In my experience, this sort of thing is usually a result of a young mother feeling like she has no choice but to abandon the baby as she isn't confident in her ability to look after the baby and she has no support from family members or the father.
"I hope she has the courage to come forward so she doesn't have to live with it for the rest of her life."
Police said they were yet to confirm details but the dead baby was possibly a newborn.
"We have serious concerns for the well-being of the baby's mother and our initial focus will be on identifying who she is," said Detective Senior Sergeant Karen Bright.
She said police needed urgent assistance.
"Anyone who wishes to speak with us can do so in confidence and we would reiterate that our main concern at this stage is the welfare of the mother," said Bright.
"We will provide another update later today once further inquiries have been carried out.
"Anyone who wishes to speak with police can call Counties Manukau Crime Squad on (09) 261 1321 or contact Crimestoppers anonymously on 0800 555 111."
And Kulukora Akau'ola, a young South Auckland woman, pleaded guilty to manslaughter after her son was found buried in a makeshift grave in the backyard of an Otahuhu house in 2011.
The court heard Akau'ola was trying to keep the birth from her parents.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7) • Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7) • Youthline: 0800 376 633 • Kidsline: 0800 543 754 (available 24/7) • Whatsup: 0800 942 8787 (1pm to 11pm) • Depression helpline: 0800 111 757 (available 24/7) • Rainbow Youth: (09) 376 4155 • Samaritans 0800 726 666 • If it is an emergency and you feel like you or someone else is at risk, call 111.