Principal Raechelle Taulu told the Herald the school's priority was to "wrap around" the woman to make sure she had all the support she needed and to support other staff and the school community.
"We have been planning for this in terms of being prepared for students to work remotely from home - like many schools," Taulu said.
"Marist is an amazing community so I know that at the end of the day we will all look out for each other."
While the school aims to reopen on Thursday, Taulu said that was dependent on contact tracing being completed. "That's step one - we can only go as fast as we can."
The Auckland Regional Public Health Service is tracing and contacting close contacts of the woman. Close contacts will also need to stay home for 14 days and watch for symptoms.
People who had been close to close contacts are not themselves at risk, parents were told in today's letter.
Parents were also asked not to post any identifying information about the woman on social media as that could lead to bullying or online abuse.
The neighbouring Marist Primary School has also closed, effective immediately. The Catholic school told parents the board had decided to close because of familial links between the two schools and interactions between staff and students.
It would be closed for a minimum of 72 hours - but the school said it was not clear how wide ranging contact tracing would be.
A skeleton staff would stay at the primary school for parents who could not make arrangements straight away or for children of essential workers like health, emergency and supermarket workers.
It comes after the parent of a Mt Roskill Grammar School student was found to have the virus. The man returned from Europe on March 12 and attended the school's Tongan Fiafia event that evening, before later testing positive for Covid-19.
MRGS and neighbouring schools have been informed and contact tracing is underway.
