Supermarkets can be filthy, crammed places at the best of times, but the coronavirus threat in New Zealand has pushed that to the next level. 

A Countdown spokeswoman says there was "no need to panic", urging people to shop normally, and be clean. 

"Our stores and online services are very busy, but our teams are managing this as best as we can," she said. 

There was plenty of food to go around, and no need to stockpile, she said. 

The threat of the virus has caused customers to panic and bulk-buy, with reports of shoppers spending $1500 at the tills.

Rice, pasta, canned foods, paracetamol and soaps have been the first to disappear from the shelves. 

"We'd encourage customers to shop as they normally would in our stores, and be thoughtful of others to ensure that all New Zealanders have access to the food and products they need." 

Those who are self-isolating due to the virus can order online to avoid the store and contact with others. 

 "We have processes in place for contactless deliveries for any of our customers who might be self-isolating." 

Countdown has also ramped up its cleaning processes. 

"[We have] even more cleaning and sanitising for each of our sites, including cleaning regular high touch areas every couple of hours.

"We're also providing hand sanitiser and wipes for customers to use across our network of stores." 

The Ministry of Health advised washing any produce from supermarkets before eating it, she said.   

Foodstuffs Head of Corporate Affairs Antoinette Laird said in the past month demand for groceries had "significantly increased".

"As you would expect, we have very stringent hygiene practises in place and we have been increasing the frequency of these in-store." 

Staff were across all health and safety protocols as advised by health authorities to keep themselves and customers safe, she said. 

"This includes cleaning and disinfecting measures which are in place across all stores and are aligned with food safety practices." 

They were working with stores and chemical cleaning service providers to provide additional sanitising facilities for customers, including wipes for cleaning trolley handles and hand sanitiser dispensing units which will be placed strategically around stores, she said. 

"Many stores already have these units in place and our service provider is actively working with remaining stores to get the facilities in place," she said.  

Staff were also being encouraged to stay at home if they were sick, she said.   

At busy times they were able to manage store numbers to ensure comfort and safety, Laird said. 

If customers felt unwell, they should think twice before stepping inside their local store. 

"We continue to encourage customers to follow Ministry of Health guidelines and to ask a friend or neighbour to collect groceries, if they are feeling unwell."