People are being urged not to panic buy groceries this evening after the latest level 4 Covid-19 lockdown announcement.
Long queues are already swamping checkouts and online shopping websites appear to be crashing. Home delivery time slots are reportedly booking out fast, with one person claiming the next available time to have their groceries delivered is Saturday.
Police said it will be increasing visibility at supermarkets to "provide both workers and the public with reassurance".
Countdown spokeswoman Kiri Hannifin urged customers to "keep calm".
"We'd ask customers to wear a mask when you're shopping in our stores as an extra precaution, and use the contact tracing app as you come in.
"All of our stores are open and we will have physical distancing measures in place, as well as extra cleaning and hygiene practises.
"We're seeing extra demand for online shopping and remind everyone that all our stores are open and there is plenty of food and other groceries so there's no need to buy more than you need."
Consumers are reporting supermarkets in Auckland are busy, with one on the inner North Shore already having to open all checkouts.
New World Birkenhead Grocery Manager Thilak said he noticed an increase in customers in the past half hour.
He said all the checkouts are open and there are long queues.
Thilak said there's no need to panic as there's lots of stock for everyone.
Foodstuffs NZ corporate affairs head Antoinette Laird said: "We know the news of a potential lockdown is unsettling but rest assured our stores have plenty of groceries on the shelves. And fortunately, our North Island DC has plenty of extra capacity and the team have been holding extra volumes of key essential items should it be required in a case like this.
"So, we are again asking customers to #shopnormal and be kind to our teams and each other.
"Our teams are preparing to move alert levels and we ask customers to be patient as we prepare to roll out the various safety precautions required to keep everyone safe. In the meantime we encourage everyone to scan the Covid tracer app and wear masks to protect themselves and our teams."
Further south, Andre Afamasaga tweeted an image of Petone Pak'nSave where shelves of bread were bare.
In Katikati, Bay of Plenty, Maria Sherwood posted on Twitter an image of the empty toilet paper shelves at the town's Countdown supermarket.
Case is from Devonport
The positive community case of Covid-19 announced today is a man from Devonport.
He tested positive after visiting his GP, Director-General of Health Dr Ashley Bloomfield said tonight.
His infectious period is thought to have started on Thursday, August 12.
He was not vaccinated but his wife was fully vaccinated and she had returned a negative Covid-19 test result, Bloomfield added.
"He was making every attempt to book in his vaccination," Bloomfield said.
And the Devonport man earned praise Dr Bloomfield for frequently scanning in using the NZCOVID Tracer app.
He and his wife travelled to Coromandel township on Friday and stayed for the weekend.
The man's frequent scanning had helped authorities pinpoint locations of interest.
The couple visited Coromandel and stayed at the Star and Garter hotel. The Ministry of Health has released a list of current locations of interest.
Recently, the Devonport couple had been self-isolating at home.
Prime Minister Jacinda Ardern tonight said genome sequencing would be needed to determine what strain of Covid the Auckland man had.
Ardern said every case in the country's MIQ facilities recently had been of the Delta variant.
Before 6pm, a source close to the Government said Auckland and Coromandel will go into level-4 lockdown for seven days - and the rest of the country for three days.
A pharmacy in Devonport's Victoria Rd told the Herald they had been told not to say anything before hanging up this afternoon.
A staff member at Takapuna Grammar School said they'd heard the positive case may be in the Devonport area.
The tip was "unsubstantiated" but the school was preparing for lockdown.
A post on the Devonport community Facebook page said there was apparently a community Covid-19 case today, in Devonport, not yet linked to the border.
"As a precaution could you please make sure you are wearing masks if you're catching public transport home after work today," the post added.
"If you're not comfortable catching public transport please Uber."
The posts also advised people to take devices and laptop computers home this evening in preparation for working from home.
Before the Government's 6pm announcement, Newstalk ZB's political editor Barry Soper was told the person travelled between Auckland and Coromandel.
"One of my very good sources during this pandemic ... believes this person who is carrying Covid 19 [was] not linked to the borders and he travels."
A New Zealand Defence Force spokesman said he was not aware of any military personnel involved with Auckland's new positive Covid case.
Devonport Business Association spokesman Shaulyn van Baaren said she was unaware if the community case was from Devonport.
"We will continue to monitor the situation closely and be tuned into this evening's address."