The child who died in a "tragic accident" at Piha on Saturday was found on rocks, a witness said.
The woman, who wanted to be known only as Kelsey-Ann, said she and her partner joined in the search for the 5-year-old boy when they arrived at the beach and a lifeguard approached them.
"When we turned up at the beach a lifeguard came over to us and asked us if we had seen a little boy wearing a yellow top."
She and her partner "had a little look around", and were approached by numerous other people asking if they had seen the boy.
About an hour or two later, Kelsey-Ann's partner asked a lifeguard if there was anything more they could do to help.