He said staff and students who had come into contact with the infected person would be screened for the disease next Tuesday.
Potentially infected people would keeping attending school until the screening was carried out, he said.
"We are just following the advice of the public health service who can advise us that while it is infectious, it is not as infectious as the flue for instance. It's more difficult to contract."
ARPHS Medical Officer of Health Cathy Pikholz said those who tested positive for tuberculosis would be given a chest x-ray.
Most who tested positive would be infected with a latent strain of the illness, meaning they could not pass it on, she said.
"I do want to reassure parents, students and teachers that tuberculosis is not easy to catch - it usually takes many hours of close contact with a person who has infectious tuberculosis for close contacts to be infected."
Board of Trustees chairman John Holley earlier told Newstalk ZB staff and students who had contact with the infected person would be screened.
He said it was difficult to know where the person contracted the illness.
"People travel overseas, we have people living in low socio-economic areas. Tuberculosis can mean a lot of people, it doesn't necessarily manifest itself after you first come in contact with it so there's a wide range of places where someone could have been infected."
Symptoms of active tuberculosis include a persistent cough for more than three weeks, unexplained weight loss, sweating, unexplained fever, feeling tired all the time and shortness of breath.
There are 350 to 400 reported cases of tuberculosis in New Zealand every year, according to Ministry of Health figures.
World Health Authority statistics show 1.7 million people died of tuberculosis in 2009.
- Herald Online staff
