Speaking at a press conference this afternoon, Dr Ashley Bloomfield said the person showing the symptoms was in Auckland Hospital and "being managed appropriately".
"The normal management of someone who is a suspected case of an infectious disease like this is that they have a special isolation room in the hospital and it has what's called negative pressure ventilation and that basically stops the possibility of the virus being carried out in the air, and the staff looking after that person follow very strict requirements around personal protection."
Dr Bloomfield said the evidence was confirming that the contagiousness of the coronavirus was not particularly high, and the fatality rate was below 3 percent, lower than previously thought.
He said if this was a suspected case, the public health body would be thinking about contact tracing.
"This person has met the criteria. We have a clinical and case definition on our website for a suspected case and this is the first person who has been investigated who meets that definition."
Dr Bloomfield said it was critical that people felt comfortable coming forward if they had symptoms and it was important there was no blame or shame attached to that.
"That's a fundamental part of a community or country being able to manage this situation, is that people feel comfortable volunteering if they are symptomatic, because the system then is very good at kicking into gear and to supporting and managing them appropriately."
Dr Bloomfield said the authorities needed to "ensure everything is in place" before the planned flight bringing New Zealanders home from Wuhan went ahead.
"What we're really interested in doing is identifying any suspected cases, confirming whether or not they are cases and then stopping any other transmission."
He said screening will occur before people get on the flight and there were precautions to avoid transmission of the virus from person to person on the plane.
"Health staff will be going over and screening people on the flight to ensure they are fit to fly."