Some local boaties and members of the public are also helping in the search, under police supervision.
The weather is calm, which is providing favourable search conditions.
Police continue to welcome reports from people who saw the diver's movements yesterday, Inspector Neil Banks said.
The man was wearing a black camo wetsuit and is described as tall and athletic, with medium-length blond hair.
Banks said the man was visiting his partner, who lives in Wellington, and would go diving in that spot two or three times a week when he was visiting.
He has been diving for several years.
"Makara is a rugged piece of coastline. In terms of foot-searching it's very challenging," Banks said. "Our land search teams that have been out in the field today have had a jolly hard day's search."
Banks said police still "absolutely" hoped to find the man alive.
Anyone with information can call Wellington District Police on 04 381 2000.