The woman at the centre of the latest Covid scare is quite likely to have contracted the new highly-contagious variant, according to a health expert.

Auckland University professor Des Gorman today told Kate Hawkesby it was most likely the 56-year-old Northland woman picked up the infection while she was in managed isolation at the Pullman Hotel.

The woman arrived in the country from Europe on December 30 and, after testing negative twice, left managed isolation on January 13 to head home south of Whangarei.

Over the next eight days she visited nearly 30 supermarkets, clothing and electronic stores, cafes, restaurants, a gallery, plant centre, museum, pharmacy, vehicle testing station and tavern.

She is now in isolation at her home with her husband, who has also been tested and is awaiting the results.

Today Gorman said the affected communities should be getting tested immediately and going into isolation until test results were back.

"It's quite likely to be one of the contagious strains and it's quite likely that she acquired this through quarantine."

Tests have so far detected 36 people arriving in New Zealand with the contagious strains since they emerged late last year - 29 samples of the UK variant and seven of the South African variant.

Gorman said it was a matter of hoping she was in affected businesses between Helensville to Whangarei when they were quiet.

Whether Covid was now in the Northland community would depend on how many people she came into contact with.

He was concerned the list included businesses that attracted lots of customers through the doors like grocery stores, cafes and a pub.

"It really will depend on whether she's a super spreader."

What was going to help health authorities and perhaps limit any community outbreak was her use of the contact tracer app.

"The fact that she has recorded where she was will expedite the contact tracing and it needs to because frankly during the last Auckland outbreak the contact tracing was nowhere near good enough or fast enough."

Gorman repeated his call for the Government to tackle the outbreak with more urgency and rigour.

"I think the response to everything has been too slow," he said.

He said those in isolation should not be allowed to mix and mingle in facilities as they were often seen doing in exercise and smoking areas.