One person is being treated for Covid-19 at Auckland Hospital and is reportedly in a stable and improving condition.
But anyone suspected of being "likely" to have it is also put in isolation to reduce exposure, Thomas said.
What happens when someone is suspected of having coronavirus?
When someone first gets to a hospital complaining of flu-like or respiratory symptoms, medical staff do an assessment for "epidemiological features" to determine how likely they are to have Covid-19, said Thomas.
This includes asking questions about whether they've come from or had contact with someone from China, Iran, Italy or another country with a high infection rate.
The patient is also examined for respiratory symptoms, especially if it's shortness of breath, fever or a cough, which could all suggest pneumonia.
Thomas said if the patient fills all those criteria, they'll be put in isolation.
What happens in coronavirus isolation?
Once the patient is identified as being a "likely" case, they're taken into a negative pressure room which sucks the air from the room into the sky above to prevent it escaping into the hospital's corridors.
If there's not a negative pressure room available, they're put in a normal room and the door is kept shut, Thomas told the Herald.
Doctors and nurses treating the patient wear special isolation clothing, including yellow paper gowns, gloves, an ordinary surgical mask, and then a shield which covers their whole face.
Thomas described the shield as a plastic version of a welding mask.
This protective gear must also be put on and taken off in a specific order, interspersed with hand washing, while a colleague sits with them and makes sure they're doing it correctly.
Thomas said most medical staff know these isolation requirements are part of their job, but if they felt particularly uncomfortable, wouldn't be forced to help treat that patient.
"As you can imagine, it's not too hard to find nurses and doctors who will do all of that pretty meticulously, and see the need for it.
"They accept that that's part of their job, that it's scary for them, and that it's scary for their wives and husbands and their children.
"But that's something they've signed up to with this job that they're doing."
Meanwhile, the patient themselves is given a simple, surgical face mask "so that the coughing for some degree is contained, and isn't going to be splattering all over the place".
However, if the patient is coughing uncontrollably, then they'll be required to wear a N95 mask which can fasten securely to their face.
The patient then undergoes a number of tests, including checks on their lungs and chest, and samples are taken to check for Covid-19.
Doctors and nurses will continue to test for Covid-19 until they're certain the patient doesn't have the illness, or their suspicions are proven right, as in the case which was confirmed on Friday.
Someone is confirmed as having coronavirus - what now?
The patient remains in isolation until they're asymptomatic - meaning they're better and no longer have any symptoms.
But as they're in isolation, people going into the room is kept to a minimum, which means medical staff who are set to enter their room anyway are the ones who'll deliver their meals.
While they're still able to have visitors who'll all have to wear the full isolation attire, they're asked to keep numbers to a minimum.
"The advice would be, just your nearest and dearest - not the whole whānau."
To help pass the time, patients are allowed to use devices, like any other patient.
The Herald on Sunday reported at the weekend that protocols vary by a patient's condition and hospital.
In a suspected Ebola virus disease case in Christchurch Hospital in 2015, later described in a paper by Dr Ruth Barratt, the patient was in an isolation room for more than 60 hours until testing negative.
Coloured tape of the floor around the patient's room was marked in red, orange and green zoning. Waste was double-bagged and put in hard-shell drums with another packaging liner.
Disposable bed linen was used, and touch points and surfaces wiped daily with a sodium hypochlorite solution. When possible, disposable medical equipment was used.
