One is a close contact of the existing student case.
The two new cases were announced ahead of the usual 1pm (local time) announcement by COVID-19 Response Minister Chris Hipkins at the health select committee today.
Mr Hipkins said of 31 close contacts at the school, there were 28 negatives and two sets of results were pending.
Out of the wider school population, officials asked for 1523 people be tested.
Of those, 1089 results were back of which one was positive and 433 were still pending, Mr Hipkins said.
Director-General of Health Dr Ashley Bloomfield said one of the new cases was a classmate of the student who had tested positive.
She was being treated as a close contact and was isolating, as were her family members.
The other case was her brother, who was categorised as a casual-plus contact because he was a student at the school.
“But in this case it’s most likely that the chain of transmission is from our original case to the classmate, who’s then passed it on to her brother,” Dr Bloomfield said.
“Obviously we will be looking very carefully at whether there are any other positive tests coming out of the high school among those casual-plus contacts.”
All household contacts of the two new cases would be tested if they hadn’t been tested already, Dr Bloomfield said.
“Then we go back that 48 hours prior to when they were deemed to be infectious, which is prior to either symptom onset or a positive test.
“We look if there are any exposure events, a bit like we have with all the other cases, and then we’ll send any notifications out about possible exposure events. Those people will be asked to isolate and have a test.”
Two of the three family members at the centre of the outbreak had travelled to New Plymouth before experiencing symptoms or realising they had COVID-19.
Most results from tests related to the trip were back and all were negative.
Two results from an accommodation location were still to come, Mr Hipkins said.
Auckland is currently at alert level three, while the rest of the country is at alert level two.
A briefing to announce any changes or extensions to current levels is expected at 4.30pm (local time) today.
Aucklanders, including students, are asked to stay home.
Those identified as contacts or who were at the locations of interest are being asked to get tested.
This content first appear on 9news