A waiting game to see if a woman who has tested positive for Covid-19 since leaving managed isolation has passed the virus on

The 56-year-old went through managed isolation at Auckland's Pullman Hotel where she tested negative twice - before returning a positive test late on Saturday.

The woman visited about 30 locations in the southern part of Northland in the last few days.

Director-General of Health Dr Ashley Bloomfield says she has four close contacts - a household contact and some retail contacts - who are being isolated and tested.

He says the other settings include, cafes, restaurants, tourist attractions and a couple of AirBnBs with only fleeting interactions with staff or others.

Covid-19 Response Minister Chris Hipkins says about 600 people who have left the Pullman since the first of January are being contacted and asked to get a test.

He says staff who have been working at the hotel are being tested regularly.

But Hipkins says they're checking that anyone who hasn't been tested in the past few days gets an up to date test.