Coronavirus: Jacinda Ardern's plea to New Zealand as shoppers flood supermarkets

The Prime Minister has again pleaded with shoppers not to panic buy, and she's promising supermarkets and pharmacies will stay open no matter what.

Some shoppers are now deciding to grow their own veggies at home  - but garden centres are now struggling to keep up with New Zealanders' newfound green-fingers.

A video taken outside Glenfield Pak'nSave showing a shopping frenzy goes on for 45 seconds.

It's scenes like this that have drawn a strong rebuke from the Prime Minister.

"I cannot reiterate this more clearly or firmly enough. We will continue to have food supply in New Zealand," Jacinda Ardern said.

Despite all the advice, shoppers continue to flood the supermarkets - and Ardern says it could deprive people of what they really need.

"There'll be families who need formula, and if you panic-buy that'll be a family who may need that immediately where it won't be available," she said.

All supermarkets in New Zealand have united, publishing an open letter asking New Zealanders to only buy what they need, not to stockpile - and to be kind to fellow shoppers and staff.

The Prime Minister says even if New Zealand enters 'alert stage four', essential services like supermarkets and pharmacies will remain open and the Government is working with them, to support them to do so.

The prospect of self-isolating and self-sustaining has led many New Zealanders to buy seedlings and grow their own veggies.

"This is kind of the silver lining to a degree for us. It'll get people back into the garden. It'll get people who don't normally garden gardening," St Lukes Kings Plant Barn manager Simon Andrews says.

But Andrews says over the last week, demand has skyrocketed - and the growers can't keep up.

"It's certainly bigger than we expected by a long shot, and the growers. And now we're just playing catch-up," he says.

It means shoppers come in expecting peppers - and are left with parsley. But they're still finding the positives.

"It's going back to the old ways. Shopping less, gardening a bit more," one person told Newshub.

Andrews says growers are now planting at four times the rate they normally do - and expects to have more stock by the end of next week.