"This is very tragic for the family of the young man who died, and for everyone at the camp," he said.
"The risk of the young people or staff being infected is very low, as the meningococcal bacterium is only spread by very close contact, or many hours of contact, with an infected person.
"The other young people at the camp are safe and are being well looked after by St John, who were sending additional support staff.
"The camp would continue until tomorrow and parents have been told of the young man, and given information on symptoms for when the young people return home," Barnfather said.
St John Youth Northern Region hosts the event for children in their cadet programme aged between 11 and-18.
Campers participate in activities like kayaking, sailing, swimming, and hiking on Motutapu Island.
St John's cadet programme is dedicated to children aged 8 to 18 and trains them to learn first aid, health care, leadership and life skills.
They meet once a week during the school term at their local division and are grouped into various levels for training, competitions, events, camps and social activities.
Outside of their weekly divisional meetings, St John Youth members partake in competitions and first aid scenarios, adventure activities, and drill and formal ceremonies.
Northland's Public Health Unit was also talking to the family about who else might have been at risk in the previous seven days in which the young man was infectious.
"Meningococcal disease is a serious and sometimes fatal disease, and can be difficult to diagnose, so we are providing information to the young people and parents so they can be alert for symptoms," Barnfather said.
"It can look like the flu early on but quickly gets much worse. It is important to get early treatment."
Symptoms included some or all of the following: fever; headache; vomiting; feeling sleepy, confused and delirious; loss of consciousness; joint pains; aching muscles; stiff neck; dislike of bright lights; or rashes, purple or red spots, or bruises.
Other symptoms in babies and infants include being unsettled, floppy or irritable, refusing drinks and feeds, and becoming harder to wake.
"If you or anyone you know has these symptoms, don't wait."
People should phone a doctor or Healthline on 0800 611 116 immediately.
There was an average of 29 cases of meningococcal disease annually in Auckland, however numbers varied from seven to 47 in 2017.