The two latest Covid-19 cases in Auckland may yet prove to be historical infections

The returnees who completed their managed isolation in the same facility at the same time as this week's Northland case, are being treated as confirmed cases.

Genome sequencing results today, and serology results tomorrow, are expected to help develop the picture further.

Auckland University microbiologist Siouxsie Wiles says these results are key to figuring out the next steps.

She says if they are true positives, we need to figure out when they were infectious and whether that was in the community.