"No one expects a visit to the beach to end this way," Eastern District Commander Superintendent Jeanette Park said.
"This is a devastating outcome for this family and our thoughts and aroha are with them.
"I also want to acknowledge the Police staff and member of the public who went into the water to rescue the child. This is not the outcome they had wanted and we will ensure they are also provided with support."
A rāhui is expected to be put in place and further details will be provided once available.
Coastguard duty officer Henry van Teul said the coastguard had been stood down at 4.10pm.
Ambulances, fire crews, police and a rescue chopper attended the scene just south of the National Aquarium of New Zealand.
In May this year van Tuel said he had personally been involved in two rescues along Marine Parade.
"One successful and one unsuccessful - I'm all too aware of the dangers of Marine Parade, especially when the surf is running."
In April this year a coroner's report found a 7-year-old who drowned off Te Awa in 2020 had been playing in crashing waves with his twin brother before he was washed away.