When police arrived, relatives of the two boys had managed to pull them from the water.
The 11-year-old boy was unable to be resuscitated and died at the scene, while the 7-year-old was "safe and well", police said.
Surf Life Saving northern region manager David Butt said the young boy was not breathing when he was pulled from the water, and lifeguards tried to resuscitate him.
"The rescue helicopter then showed up and took over CPR and at that stage the helicopter paramedics called the patient deceased."
The rescue helicopter's chief pilot, Pete Turnbull, said they were in the area when they got diverted by police to the incident.
"We landed adjacent and our St John people on board continued CPR [on the boy] for about 30 minutes."
Mr Turnbull said he was unsure as to how the child had got into trouble but said the water was calm.
"It was being enjoyed by pockets of people every few hundred yards down the beach."
Water Safety New Zealand said the drownings over the holiday period, which ran from 4pm on Christmas Eve to 6am today, was a "huge disappointment".
The toll does not include the death of surfer Simon Camp, or a man who went missing while on his boat at Hihi beach, as the circumstances of both deaths were unknown.
Water Safety chief executive Matt Claridge said six of those who drowned over the holiday period were men, while one was a preschooler.
"Anything other than zero would have been a disappointing result but for the number of drownings to be more than last year's festive period - and to include a preschooler - is gut-wrenching," he said.
Mr Claridge said the year was off to a tragic start, with two of the seven deaths so far occurring in 2015.
"Two families are already without a loved one and we're less than a week into the New Year."
Water Safety also released it provisional drowning toll for 2014 today. There were 90 deaths -- a 16 per cent decrease on the 107 deaths in 2013.
Meanwhile, the police dive squad recovered the body of a Far North man missing near Hihi yesterday.
The man went out on his boat from Hihi Beach on Saturday and failed to return to shore.
Police believed there were no suspicious circumstances and said the man's death would be referred to the coroner.
A funeral for Jarod Lineses, who was swept out to sea on Ninety Mile Beach on December 27, will be held in Auckland tomorrow.
Holiday water deaths:
December 25 - Heng Li, 25, a student, died at Uretiti Beach in Northland while setting crab pots, and Imogen Saleupolu-Mataafi, 1, drowned in a temporary pool set up in the backyard of her family's Manurewa home.
December 26 - Simon Camp, 47, died at Karioitahi Beach, 70km southwest of Auckland, while surfing on a board he got for Christmas.
December 27 - Jarod Lineses, 16, was swept out to sea on Ninety Mile Beach at Hukatere in the Far North. His body was found on New Year's Day.
December 29 - Terangi "Toots" Woonton, 59, and Kairangi Samuela, 53, died when their 5m vessel was swamped by a wave while crossing the treacherous Manukau Bar.
January 1 - Kris Wichman, 36, drowned in the Patea River near Taranaki on New Year's Day, after rescuing his niece and two daughters from the water.
January 1 - Wayne August, 42, was seen by beachgoers walking into the surf at New Brighton beach in Christchurch wearing long pants and a T-shirt on New Year's Day. Witnesses said he appeared to be drunk.
January 4 - The police dive squad recovered the body of a Far North man who went missing near Hihi Beach on his boat on Saturday. Police believed there were no suspicious circumstances and said the man's death would be referred to the coroner.
