If the stampede on paint and DIY supplies is any guide, some pristine houses and gardens will be on show in a month's time.

A day after supermarkets were inundated as Prime Minister Jacinda Ardern declared a nationwide month-long lockdown from Wednesday night to combat the spread of coronavirus, other stores classed non-essential struggled to cope with demand.

Bunnings Warehouse and Mitre 10 Mega outlets in the main centres had jam-packed carparks, some empty shelves and steady streams of customers stocking up for DIY jobs, while paint retailer Resene had to close some stores because they simply ran out.

Resene marketing manager Karen Warman told Stuff at least two of their stores had to shut by late morning on Tuesday as they had run out of paint.

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"Resene is experiencing some of the busiest days we have ever had, yesterday [Monday] and now today," Warman said.

ROSS GIBLIN/STUFF Bunnings Porirua and other DIY stores were inundated on Tuesday.

"One of our stockists sold over a week's worth of paint in one day on Monday. Many homeowners are trying to get paint for projects to keep themselves busy at home over the next four weeks - everything from painting the house or rooms, to paints for art and craft projects."

Warman said Resene had extended its opening hours to try and spread out the demand and minimise customers at any one time, "which helps to keep everyone safer.

"Our staff are limiting the number of customers in store at any one time, encouraging hand sanitiser use and asking customers to keep a good distance from staff and each other and to be patient.

"Luckily our stores are quite spacious which has helped. All of our representatives, who would normally be on the road, are helping in store also to help people get what they need and get back home."

The car park at Mitre 10 Mega in Glenfield, on Auckland's North Shore, was so full some resorted to parking across accessways, prompting some frustrated announcements on the store PA.

Inside, the rush seemed to be on building products and plants, suggesting plenty of locals were planning to spend their month on DIY projects.

If you wanted vegetable seedlings, though, you were out of luck - the vege aisle, which on Monday still offered a few punnets of brussels sprouts, was empty.

Chris Fisher, Mitre 10 general manager merchandise, said: "Mitre 10 has experienced a significant lift in sales of DIY supplies over the past few days. We have noticed a considerable increase in the sales of paint, vegetable seedlings, cleaning products and batteries amongst others."

Mitre 10 Mega in Botany, Auckland, said on its Twitter page it would be open late on Tuesday and Wednesday to cope with demand.

On its website Mitre 10 offered a one hour 'click and collect' for shoppers to pick up their purchases, as well as a delivery service for people in self-isolation.

In stores its precautions included increased cleaning and sanitising to keep surfaces such as door handles, trolleys, toilets and payment counters clean at all times.

"Our stores support self-distancing in-store but team members remain available to provide any assistance as you need it," it said on its website.