He was concerned at the prospect of a rogue wave rolling in and washing them off.
"I wonder whether the concrete pad should be caged all round and not just at the back part."
Napier City Council infrastructure director Jon Kingsford agreed there did appear to be an issue in a situation the heavy seas and high tides would have had a part in bringing on.
He said the council was committed to the health, safety and welfare of the community and visitors to the city and seafront.
"When the grill was installed the gravel levels were much lower and gaining access to the end of the culvert was more difficult."
He said council had considered fencing or caging the concrete pad but believed that in turn could have produced another potential risk - "of children being caught inside the cage in the event of rough seas or rogue waves".
Council engineers would now be reviewing the location of the present grill and would also be putting up signs.
"Reminding kids, parents and caregivers of the risks of playing on or around the pad."