An epidemiologist says the next two days will be crucial in determining whether Auckland will drop down to Alert Level three on Monday

There were 20 new cases today all in Auckland, but only one of them was a mystery case.

Otago University's Michael Baker says the number of unlinked cases will determine whether Auckland shifts.

Professor Baker says testing will also be key.

He says anyone who has symptoms or has been at a location of interest should get tested.