A body has been found at Sumner Beach in Christchurch.
Police said the body was discovered by a person jogging on the beach about 4.35am.
Emergency services were at the scene and police were trying to identify the body, which has now been removed.
Police could not yet publicly confirm the identity until a post-mortem had been completed, they said.
Jack Sutton, 14, went missing off nearby Scarborough Beach on 5 February.
RNZ's reporter said members of the family were at the beach this morning, where a large cordon had been set up.
Sumner Lifeboat Institution coxswain Blair Quane said the body's location and tidal drifts indicated it was likely to be that of the missing boy.
He paid tribute to Jack's mother for her positivity throughout the ordeal.
"She's been amazing, you know given the circumstances, to stay there since the boy went missing, she hasn't gone home, she's stayed on site the whole time.
"She's been as positive as you can be in this sort of situation."
The Sumner community has supported the family, providing a camper van and portaloo, as well as food for the search crews, Mr Quane said.
Jack Sutton's family have been getting help from Victim Support.
Surf Lifesaving southern regional manager Stu Bryce said the death was a terrible tragedy and he had advice for people to avoid any repetition.
"Always stay within your limits and swim with some friends," he said.
"If you are in the water, have a lot of respect for it as the whole coastline has the ability to be dangerous and should be respected.
"People should enjoy the water, [but] they should definitely stay within their limits and swim between the flags if there are flags."
Mr Bryce said there were rips on that stretch of coastline most of the time.