The appearance of another Covid case at South Auckland's Middlemore Hospital is raising questions

The patient presented at the emergency department with no signs of infection and was swabbed as part of wider hospital testing.

No other cases have been detected in their household yet.

Five previously reported patients also arrived at the hospital for treatment - unaware they had Covid-19.

All of them have now been linked to the Auckland outbreak.

Otago University epidemiologist Michael Baker says cases going to hospital is expected - as that's where sick people go.

He says this person with no signs of infection, raises questions about whether his symptoms were completely unrelated or if it was an unusual presentation.

The latest Middlemore case was the only mystery case yesterday - and there are now 10 mystery cases from the past 14 days.