There are 13 new cases of Covid-19 in the community in Auckland today and one in managed isolation.

Director-General of Health Ashley Bloomfield says the one new case in managed isolation is a woman in her 30s who arrived from the Philippines.

There are a total of 36 active cases in New Zealand. 17 cases are being considered as community cases with all going into quarantine.

Dr Bloomfield says that one of the new cases is a student at Mt Albert Grammar School, as was made public this morning.

"The student was not symptomatic while at school and has not been at school since they became unwell and got tested so the chance of exposure ... is low at this point."

Dr Bloomfield has confirmed that three of the people who have tested positive are workers at Americold, and seven are family members of the initial cases.

One person who has tested positive is an employee of Finance Now, and another person who has tested positive is their family member. There is also one new probable case in the community, which is also linked to the outbreak.

One of the people who tested positive visited an aged care facility in Waikato. Anyone who has visited recently will be notified.

Dr Bloomfield is not naming the facility yet as residents there are still being notified.

Discussing the family who had Covid-19 and went to Rotorua, he says the family checked in to Wai Ora Lakeside hotel at 3.30pm on 8 August. They visited the Herbs and Spice Thai restaurant at 7.30pm that day. On 9 August they visited Pak'nSave at 3.30pm, at 4pm they went to Skyline Gondola and Luge.

On the 10th, the Monday, the made a day trip to Taupō and made a boat trip. All the people on the boat trip have been identified and contacted.

Then they returned to the Heritage Farm and Art gallery.

He says all new positive cases will now be treated in quarantine facilities.

"It will help us avoid any further inadvertent spread."

Dr Bloomfield reminded people that "there is no blame or shame in having Covid-19. The virus is the problem, not the people."

Laboratories processed 6006 tests yesterday. Dr Bloomfield says the total swabs collected yesterday was well over 10,000 but because the cutoff time for reporting is midnight not all of the results have been included.

Two more pop-up testing sites have been stood up in Henderson and Airport Oaks.

The testing centres in Rotorua and Taupō have extended their hours.

Dr Bloomfield says testing is available to any businesses that request it.

He says for the first time this morning the Ministry of Health has used the alert function on the NZ Covid Tracer app.

He says another 338,000 people have registered on the app.

GSR is continuing to lead efforts on genome sequencing.

"What we do know is that the pattern of the genome sequencing of the new cases most closely resembles the cases in the UK and Australia."

'We have a plan' - PM

Auckland has entered its second day of alert level 3 lockdown, with a decision imminent on whether or not to extend it before Friday midnight, when the order is due to end. The rest of New Zealand is at level 2, and aged care facilities are in lockdown nationwide.

Prime Minister Jacinda Ardern says there is more information needed to find the source of the Covid-19 outbreak.

"If you live in Auckland, work from home if you can, if you go out of course it's for essential items."

"When you leave your home we encourage you to wear a face covering."

Ardern says you can go to your local GP for a free test. If you are symptomatic you should call ahead so they can prepare for you.

She is asking people who live in Auckland to stay put - there are reports from police of some people trying to travel to their holiday home.

By 7am today 17,000 vehicles had been stopped, 312 were turned back.

"Going hard and early is still the best course of action ... remember things will get worse before they get better."

"We have a plan, we have acted quickly, and we will continue to roll out that plan."

There will be another briefing at 1pm tomorrow, followed by a further extra briefing at a time yet to be confirmed where the prime minister will announce the decision on alert levels.

Dr Bloomfield says at this stage it is not thought necessary to expand restrictions, despite the movements of positive cases to Waikato, Rotorua and Taupō.

"At this point in time it seems very very clear that the locus of the outbreak is in Auckland."

He says all the new confirmed cases came through last night and he found out about them this morning. Any pertinent information about travel of positive cases will be made public, he says.

Dr Bloomfield says he was notified about a positive swab result yesterday in Wellington, but it was unusual and further testing came back negative.

Asked about moving positive cases to quarantine, Dr Bloomfield says it differs from last time because at that time the facilities were still being set up part way through the lockdown.

Dr Bloomfield says there was some reservation from those in the community with Covid moving into managed isolation but he said those concerns have been alleviated.

Speaking on the demonstration by residents in Whangārei this morning, Ardern says any form of misinformation being spread about Covid-19 is concerning but she thinks most New Zealanders will see through it.