An expert on disaster psychology says panic buying for coronavirus isn't rational but it is understandable.

The first New Zealand case of coronavirus was confirmed on Friday with a person in their 60s now improving in isolation at Auckland City Hospital.

That's sparked a flurry of panic buying of products like toilet paper, rice and bottled water.

Massey University psychologist Maureen Mooney told Mike Hosking stocking up on water bottles may not be sensible, but it's a normal reaction in the circumstances.

"We change our rational behaviour a little bit, and would have thought 'we need to preserve ourselves'. They would have gone into fight-flight mode."

She says the queues at the supermarkets should now be starting to ease.

"When we're rushing and reacting in an emotional way, we don't think about things as clearly. So probably most of these people are now starting to think 'maybe we didn't need to have such a reaction'."

The Ministry of Health says the risk of a coronavirus outbreak remains low for the New Zealand public.