Despite calls for calm from Prime Minister Jacinda Ardern during the coronavirus crisis, panic buying has forced supermarkets in Auckland to close their doors or bar customers due to high demand.

And Spark says Kiwis made more phone calls than ever before as news of the lockdown emerged.

Earlier today the Government raised the coronavirus alert status to level three.

In 48 hours the alert level would be raised to level 4 - "stay at home" instruction, schools and businesses closed except essential services, severely limited travel - and will remain in place for a minimum of four weeks.

Roughly half of those queueing are wearing masks. Some are also wearing disposable gloves.

Staff are allowing one customer in as one leaves.

One staff member can be heard shouting, "Please stop, keep your distance, there is plenty of food".

He said he has hired 20 people in the last week just to keep up with demand.

A queue of more than 100 queued outside Whangarei Pak N Save at 3.30pm, with staff only letting small groups in as others departed.

There were similar scenes in Auckland's Grey Lynn. A woman at Countdown Richmond Rd said cars aren't being let into the carpark at 3:30pm. She said shoppers were also having difficulty getting into Farro across the road as well. By 5pm a lot of the initial congestion had eased.

Wairau Park Pak'nSave reportedly had similar overcrowding issues.

Chemist Warehouses around the country were also experiencing high demand. A voicemail message said shops were experiencing "unprecedented demand for pharmacy items", including prescription medications.

Rolleston Countdown is only allowing two people into the store at one time, with one shopper waiting outside the store for 30 minutes.

Z Energy reassured motorists there is sufficient fuel supply at all sites and not to panic.

"Our service stations and truck stops are considered essential services and will be able to stay open to support all New Zealanders. We have plenty of fuelof all grades at all sites, and as with the supermarkets we encourage the public to fuel up normally. Pumps will remain open during the self-isolation and we encourage all customers to start pay at pump and contactless payments options (including Fastlane and Sharetankin our Z App) as soon as possible."

Mike Bush, Commissioner of Police, Strategic Operations Oversight, said today that police will intervene to keep supermarkets safe and maintain order if needed.