The incident at Goat Island came after police urged people to be safe around water after number of water-related deaths in recent days.
A swimmer died in Upper Hutt after failing to resurface at Hutt River, in Kaitoke Regional Park, early on Tuesday morning. A rāhui remains in place there too.
Regional council spokesperson Al Cross said mana whenua Te Āti Awa blessed Te Awa Kairangi - the Hutt River - on Wednesday. The rāhui, which restricts access to a river pool area 20m upstream from the swingbridge, is likely to last until Friday.
It does not cover any part of the Pakuratahi River, which flows past the campground.
On Boxing Day a man died in a water incident at Cape Runaway on the East Coast, and later that night a person died after a water incident in Pukekohe in Auckland, despite receiving medical attention.