Three people attended an open home at a household where three family members tested positive for Covid-19.

The viewing took place at the Papatoetoe home of Cases I, J and K on Saturday before the Papatoetoe High School student and her siblings tested positive for the virus on Monday.

The schoolgirl stayed in a bedroom throughout the event, according to The Spinoff.

The real estate agent and three attendees were all contacted by Public Health officials on Tuesday after the tenant tested positive.

There are no new cases of Covid-19 in the community and three in MIQ, the Ministry of Health has reported.

One of the three cases in managed isolation today is a historical case and not regarded as infectious.

Of the 11 positive cases linked to Auckland's February cluster, all remain in the Auckland quarantine facility.

Genome testing results now available for Case K has shown it to be the B.1.1.7 variant and again very closely related to the genome sequence for Cases A and B.

"This provides further reassurance that the cases from the additional household announced on Tuesday have not appeared from elsewhere in the community," the Ministry of Health said. "All cases that have been sequenced in this cluster are genomically linked and are connected to the cases at Papatoetoe High School."

There were now 31 close contacts at Papatoetoe High linked to Case A, the ministry said.

One of these tested positive (Case D). All others have tested negative for COVID-19.

The remaining students and staff at the school have been designated as casual plus contacts of Case A.

As at 8am today, there have been 1525 casual plus contacts identified at the school.

"Excluding the three positive cases (Case E, I and J), 1490 have returned at least one negative test result since February 15," the ministry said. "We have asked all these casual plus contacts to have an additional test on or after February 22. So far all results from the additional testing have been negative."

"We continue to work closely with the school to ensure all those in the school community who need to be tested are. Where necessary, this includes visits to students homes to make sure people are getting the support they need to access testing and remain isolated."