"Our focus today is all about locating mum."
Bright said it was too early in the investigation to disclose the baby's ethnicity or condition when the child was found.
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.
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."
High profile cases of babies dumped soon after birth
In 2009, a newborn baby was left at Middlemore Hospital after the 14-year-old mum tried to hide the pregnancy from her parents.
In the same year, a woman left her newborn baby in a rubbish bin after giving birth in a toilet on a Pacific Blue flight from Apia to Auckland.
Karolaine Maika was charged with child abandonment. The baby, who survived the ordeal, returned to Samoa where the woman already had another child.
The court heard Maika was ashamed of conceiving a child out of wedlock and tried to keep the baby a secret.
The body of a newborn baby girl was found in a South Auckland stream in 2011 at a property owned by champion harness racer Tony Herlihy.
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.
