Cassandra and Bradley Parker laid flowers on the water at Natewa Bay this week.
They also thanked members of the search teams for their efforts.
Into its seventh day, the search had yet to locate Mr Parker and the toddler.
Police said the mother's body was recovered by villagers from the Natewa Bay shoreline last weekend and a post-mortem examination was conducted.
New Zealand aviation investigator Andrew McGregor said the search teams were working well together.
He said the navy had joined the search and would be using sonar.