UPDATED: Police have found a body in the search for missing teen Lucas Cochrane.

The Police National Dive Squad taking part in the search for Lucas Cochrane have this evening located a body in a waterway in Whitianga.

Police national dive squad searches the waterway in Whitianga for Lucas Cochrane, assisted by lifeguards from Hot Water Beach. Photo: Phillipa Yalden/Fairfax NZ

Police believe it is Lucas Cochrane but formal identification is yet to take place.

The death will now be referred to the coroner.

Police and the family would like to take this opportunity to thank the many people who have been involved in the search for Lucas these last few days.

The outpouring of support from the community has been overwhelming.

At this stage no further information is available.

Earlier:

Police earlier closed off Aquila Dr, not far from the Whitianga Fire Station, and were only letting residents down the street.

Police say they located a hat believed to have been worn by Lucas when he was last seen.

The hat was found near the waterways where Police have been searching.

Earlier in the day, the police national dive squad was called in and spent the morning scouring the waterway in a new development being built off Kupe Dr in their search for the 19-year-old.

Lucas was last seen on Saturday night when left a friend's family function at about 10.30pm at the Whitianga Fire Station.

His phone was reportedly active for an hour afterwards, reports Stuff.

Police are expected to make a decision tomorrow about whether or not to call off the search if there is still no sign of him.

'It is a difficult decision but when we have covered all our options there is no choice," says Inspector John Kelly.

More than 30 people have been involved in the search for Lucas and 15 LandSAR members were searching the inner township again today from Lucas' last known point.

On Wednesday, the fourth day in the search, the focus had shifted from the land to the water.

Police divers had begun what John says was a long and methodical process.

"The rain we have had for the last three or four days has made it hard to see through."

Everybody is holding up well and the support from the community had been huge, says John.

"People driving in bringing baking and cookies, knowing the support is there for everybody, the searchers and the family has been great."

Family members gathered on the banks of the development, watching in the rain as divers took to surf life-saving IRBs and completed patterned searches of the water.

Lucas Cochrane was last seen in Whitianga on Saturday night.

Holding out hope

Across the road residents Andre and Tilly Grobbelaar were gardening in the rain and hoped the divers found something.

"For the sake of family there must be closure somehow. We just hope they find closure," says the couple.

Andre and Tilly, who moved from Auckland to Whitianga three years ago, were home on Saturday night.

They woke to find cars left outside the fire station and later heard the news Lucas was missing.

"The police came around and asked questions but we didn't hear anything, there wasn't anything suspicious."

A former policeman for 30 years, Andre had been involved in multiple search and rescues.

He said you have to start with the obvious - in this case across from where Lucas was last seen.

"It just depends on where he's walked and how intoxicated he was," says Andre.

"The obvious thing is the water, other than the marina across the road. If he walked down to the pier was it an outgoing tide, an incoming tide, you have to weigh all of those things up."

Although, based on Lucas' cellphone activity, Andre didn't think it was likely he went into the waterway so quickly.

"But you never know."

Family have spent days searching for Lucas and put out a plea to locals to check any garages or outside buildings for him.

After being briefed by police that the search was likely a recovery mission they have asked for privacy.

The Coromandel had been hit by heavy rain over the weekend and it didn't look set to ease on Wednesday with consistent downpours throughout the morning.

Overnight Whitianga has had 34.8mm of rain in the past 24 hours.

A MetService watch for heavy rain continues through until Thursday.

-Stuff.co.nz