An expert on infant abduction, who has dealt with hundreds of hospitals worldwide, says more of them are electronically tagging babies to prevent them from being snatched.
Middlemore Hospital says it is considering the move after a five-day-old baby girl was taken last night.
She was found at an Auckland house several hours later and returned to her parents early this morning.
Dr John Raburn, the director of the infant abduction response programme at the United States National Center for Missing and Exploited Children, told Checkpoint more and more hospitals are using electronic tagging, attaching the tags to the baby's ID bracelet.
He said the tags were similar to those used to prevent shop lifting.
"It does the same thing it does in retail - you get too close to the door, it sets off an alarm and it locks magnetic locks and lets security know which portal that tag is going through."
Dr Rabun said the monitors would never take the place of good staff but give support.