Mr Ellingford said it was a disappointing and regrettable incident.
"All you can do in these situations is the right action, which our guard did and was supported by police.
"At the end of the day in that situation it was the best outcome that could have happened."
Mr Ellingford said it was rare for this kind of thing to happen at Bayfair, and "quite surprising in today's world."
"But these things happen. It'snot just that they happen but how they are dealt with.
"I think it was well-managed by all involved."
Mr Ellingford said Bayfair guards patrolled the carpark all day for whatever may arise. The first response if a child is seen in a car alone was to call the police, even if the parents were visible, he said.
A police spokeswoman said police had spoken with the parents of the child.
Keep your children safe
- Young children must never be left alone in a house or vehicle - they need constant supervision. It is illegal to leave a child under the age of 14 years without reasonable provision for their care.
- Know exactly where your child is at all times. If you use caregivers, ask for references and visit them often without warning.
- If you think someone else's child is being badly treated or abused, contact Child, Youth and Family or Police. Don't hesitate for a moment to report your suspicions. It is far better to be wrong than too late. In an emergency dial 111.
Source: NZ Police