A newborn baby was abandoned in a car park with her umbilical cord still attached.

A newborn baby girl is lucky to be alive after she was found abandoned in a supermarket car park on a 37-degree day in Arizona, US.

The infant was just hours old – with her umbilical cord still attached – when she was found wrapped in a blanket in a Jonas Brothers backpack on Sunday 4 June, police said.

A passerby spotted the little girl in the Tempe carpark and took her into the supermarket, where staff called police.

In a recording of the call, released by Tempe Police, the dialler can be heard giving the address over the baby's cries. "And she is beautiful," he remarks.

The girl was taken to hospital, and Fox News reports she is alive and healthy. Arizona Department of Child Services is caring for the infant.

"This is a tragic situation but we’re thankful that the baby was found healthy," Ashley Shick, a spokesman for Food City supermarket, said.

"Everyone involved reacted swiftly with the needs of the child as the top priority."

Police have appealed for help to identify the child and locate her parents.