A Mt Roskill Grammar Student's father has tested positive for the coronavirus, according to a letter sent to parents by the school's principal.

The man arrived in Auckland from Europe on March 12 and attended the Tongan Fiafia event at the school that night for about an hour, the letter from principal Greg Watson says.

New rules requiring international travellers to self-isolate for 14 days were brought in several days after he arrived in New Zealand.

The man's child attended school most days following until March 19 and does not have symptoms, Watson told parents in the letter today.

Mt Roskill Grammar had sought "urgent advice" from the Ministry of Education and the Ministry of Health.

"Health authorities are contacting the few people who are considered close contacts. We have received initial advice from the Auckland Regional Public Health Service that most people who attended the event, and the wider school community, will not have been exposed to the person and therefore are not at risk."

While further information was being sought from both ministries, parents were pointed to
the government website covid19.govt.nz for information about symptoms of the virus.

Anyone who felt unwell should ring Healthline on 0800 358 5453.

"I'm sorry to be giving you this news," Watson wrote. "Our Roskill spirit of manaakitanga - upholding the dignity of all - will be our guide at this difficult time."

A notice has also been sent out to Mt Roskill Intermediate parents from principal Kristen Walsham and board of trustees chairman Roger Deverell, alerting them to the new case of Covid-19.

Walsham told the Herald the three schools on the Mt Roskill campus - Mt Roskill Grammar, Mt Roskill Intermediate and Mt Roskill Primary - were awaiting further advice today from the Ministry of Health and the Ministry of Education on the contact tracing process and what actions people should be taking.