Carloads of mainly young people begun arriving from early morning to add to the numbers of supporters, offering breakfast to the search teams.
At times they went in small groups out on to the jetty and sat waiting for news.
About six members of the police dive squad from Wellington began the search yesterday after several boats and a helicopter were unable to locate the youth.
Police said they were seeking witnesses to the collision.
Meanwhile, two boys, aged 11 and 12, are in hospital after they were injured in a collision between a jetski and a dinghy near Tairua, on the Coromandel Peninsula, late on Friday.
Maritime NZ said the jetski carrying a 16-year-old and a 12-year-old collided with a dinghy powered by an outboard motor controlled by two 11-year-old boys.
One of the 11-year-olds was flown to Starship Children's Hospital with broken ribs and a broken jaw and upper palate.
Today he was in a stable condition.
The 12-year-old boy was taken to Thames Hospital with moderate injuries.
With the risk heightened by the level of activity on the water in summer, especially during the holiday period, Maritime New Zealand safety inspector Jim Lilley said it was important every boat skipper was responsible.
Boat and jetski users should slow to 5 knots, or about 9km/h, when they came close to vessels or swimmers or within 200m of the shore.
Skippers were required to maintain a lookout and a safe speed at all times, he said.
Investigations were continuing.
- NZPA
