Bystanders gave the Rowan CPR until paramedics arrived, but they were unsuccessful.
The go-kart crash was one of a host of beach accidents in the Far North in the past few weeks.
A woman broke her arm in a buggy accident on Ninety Mile Beach on December 29. The day before, a teenage boy suffered back injuries in a quad bike crash at a coastal campsite near Mitimiti, North Hokianga, and another woman hurt herself while dune boarding at Te Paki dunes.
On Christmas Eve, a man is believed to have misjudged a jump on a sports quad in dunes near Tauroa Pt, suffering back injuries.
Rowan Willis' death came a week after 11-year-old Whangarei boy Jahzel Porter drowned after getting caught in a rip at the mouth of the Waipu River.
On Christmas Day, Auckland student Heng Li, 25, drowned while setting crab pots on Uretiti Beach, and two days later, Jarod Lineses, 16, was swept out to sea at Ninety Mile Beach. His body was found on New Year's Day.
Meanwhile, on Saturday the search was scaled back for a 25-year-old diver who went missing near Cable Bay last Thursday.
The man is presumed dead and the search will now involve local police staff patrolling the beach, said the head of Northland police search and rescue, Senior Sergeant Cliff Metcalfe.
Police have not named the man, who had been free-diving with a friend at the eastern end of Cable Bay.
When his catch-bag and a glove washed up on the shore three hours after he disappeared, police and emergency services began the search, but the police dive team found nothing.