Police divers are scouring a waterway opposite the Whitianga Fire Station for any clues in the search for Luke Cochrane.
The national dive squad arrived at the Whitianga LandSar headquarters about 8am for a briefing with police and search co-ordinators.
Just before 9am they headed to a waterway on the property of Hopper Developments on Kupe Dr, across the road from the station.
Divers, who are also being assisted by Hot Water Beach Surf Lifesaving crews, are enduring challenging conditions as heavy rain continues to batter the town.
Earlier in the week, a large section of the waterway was inspected by boat with searchers using sonar equipment.
However, the stretch opposite the station was shallower and thick with weeds, requiring the dive squad to manually check the bottom.
If the area doesn't uncover anything of interest, they will then move to an area across the road, occupied by homes and moored boats.
The Cochrane family have stopped by to check on the divers' progress this morning.
Inspector John Kelly said the focus today and tomorrow was re-visiting "high probability" land-based areas as well as searching key waterways.
Once they are satisfied they have searched as much as they can, a decision will be made in the next few days whether to end the search.
"It's a difficult decision but when we've covered all our options there's no other choice."
Kelly said although the temperature of the water was a bearable 16C, the constant rain affected visibility.
"It's very murky and silty. The rain we have had for the past four or five days certainly makes the water very hard to see through."
He again thanked the community for their donations of food - home baking and supplies for a barbecue - which helped keep up the energy levels of volunteers and staff involved in the search.
Kupe Dr residents Andre and Tilly Grobbelaar live next to the fire station and said they didn't hear anything from the people attending the function Cochrane was at on Saturday night.
The first they heard was on Sunday morning from neighbours, before police knocked on their door asking if they had seen anything the previous night.
Andre Grobbelaar, a former police officer of 30 years, said the fact that Cochrane's phone was active for an hour after he was last seen was interesting and it would give searchers a good radius to begin their search with.
Grobbelaar, who had been involved in many search and rescues during his time with police, thinks Cochrane may have gone further than just across the road.
When asked about the mood in the community, he said there was overwhelming sympathy for the Cochrane family and all hoped that they could get some closure by finding Luke.
"They're all just saying that they hope they find him for the sake of the family but there's no concerns that there's anything sinister. They're all just concerned that they find him."
It's day four of the search for the 19-year-old, which has today been scaled down from up to 30 LandSar searchers to about 15.
Kelly said yesterday the main difficulty had been the wet weather. There have only been very brief respites in heavy downpours.
Over the past three days LandSar crews have scoured, scaled and searched the high and low lands, beachfronts and creeks of Whitianga.
Kelly said yesterday that he had briefed the family that it was now a search operation, not a rescue.
They had taken the news hard and after public appeals by Luke's father, Dave Cochrane, and mother, Catherine Tamati, over the past 48 hours, they were now seeking privacy.
The search teams had combed about 80 per cent of the township and were yesterday checking the remaining 20 per cent.
Crews were out again knocking on doors asking residents if they'd seen anything and if they could check their garden sheds or under dense bush.
Boats moored in the harbour will be included in the search, which will also stretch out to Tapu-Coroglen Rd and the 309 Rd, although police said there was nothing to suggest Cochrane had left the town.
After appeals for information, police have received about 12 calls from members of the public.
Catherine Tamati told the Herald they would remain in Whitianga until their son and brother was found.
She, and police, thanked members of the Whitianga community for the help and donations of food received so far.
More and more friends and family gathered at the search headquarters near Whitianga Airport yesterday hoping for news and to help search.
Nineteen-year-old Luke is European, 1.82m in height and of medium build with short, sandy-coloured hair. He was wearing a black T-shirt, dark blue jeans, a black peaked cap and white, red and blue Nike shoes.
Anyone with information is urged to phone police on 111.