Fire crews were called to St Kentigern's School for girls in Remuera this morning after a fire broke out in the school's gymnasium.
A Fire Service spokesman confirmed the alarm was raised at 9.50am.
A Fire Service spokesman said five adults were being treated by ambulance staff for smoke inhalation.
He said five fire crews attended the blaze in the school's gymnasium.
The spokesman said the fire had been extinguished and had not spread to other buildings.
There were no other injuries.
The single sex independent Presbyterian primary school is on Remuera Road.
St Kentigern Girls' School principal Juliet Small said the fire had damaged the ceiling of the hall but all pupils at both the school and preschool were safe.
"We have had a small fire at school this morning, in the ceiling of the school hall.
"All students and staff at both school and preschool are safe - there are no injuries, " she said.
The Fire Service had given the all clear for children to return to classes and school would run as normal for the rest of the day.