Two of the new Covid cases travelled to Rotorua while showing virus symptoms and visited tourism spots.

The Ministry of Health is working to establish where they visited in Rotorua. People in Rotorua will need to be vigilant, director general of health Ashley Bloomfield said.

If there is another case in Rotorua a nationwide response will be necessary. The woman, in her 20s, travelled out of Auckland last weekend.

The woman and two young children visited tourist attractions, Bloomfield said.

None of the people who tested positive the community needed hospital-level care, Bloomfield said.

"I know that the virus remerging in our community has caused alarm and the unknown is scary. That causes anxiety for many of us," Bloomfield said.

The family who is positive is still in isolation at home in south Auckland and a decision hasn't been made about whether they will be moved to a quarantine facility, he said.

"We are working hard to put together the pieces of the puzzle as to how this family got the virus. We are testing all close and casual contacts," he said.

Bloomfield said there are no results of tests of other members of the family to report yet.

Once authorities found about the positive test, both the case and the family were contacted and isolated at home and all were tested. The trip to Rotorua took place last weekend. The woman and one of the pre-schoolers have tested positive, Bloomfield said.

"The family visited a number of tourist venues while in Rotorua," he said.

When PM and Bloomfield found out about new cases

There is no lockdown in Rotorua because everything at this stage points to the source of infection being in Auckland, Prime Minister Jacinda Ardern said.

"I have heard suggestion that we may have had this information than we have said. There is no reason why we would ever do that," she said.

"I do worry that those kind of theories do nothing to support what needs to be collective action by all of us."

We needed to have a certain amount of information to inform the decision of moving Auckland into alert level 3, Bloomfield said.

Bloomfield was texted about the cases at 2.40pm yesterday. He called the Counties Manakau DHB chief executive about 2.45pm and they had a zoom meeting about seven minutes later, he said.

Ardern and Bloomfield reiterated the timeline of when they were told of the positive test result yesterday afternoon before the announcement of lockdown at 9.15pm last night.

Genome sequencing may be able to reveal where the new cases originated from and whether it was connected to an isolation facility.

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130 colleagues of positive case isolating in Auckland

130 people who work with the man who tested positive in a finance company are considered close contacts.

Three of the husband's contacts are symptomatic and isolating at home.

"None of the workplaces where there is a risk are public-facing," he said.

One hundred and forty people are standing by to support Auckland Regional Public Health with contact tracing. Healthline is very busy and has additional staff on, he said.

Tens of thousands of people are expected to be tested over the coming days.

Bloomfield said the public health department wanted to see if the environment of the workplaces contributed in any way to any spread of the virus.

"The best thing we can all do now is face this together ... to comply with key public health messages ... and we are also recommending the use of masks, particularly in Auckland," he said

We have seen in other countries and jurisdictions where a resurgence occurs that it is incredibly important to act early," Bloomfield said

No decision on whether election will be put off

Parliament was due to dissolve today at 11am but it has been deferred by at least a few days.

Dissolution has been extended to Monday.

Options around the election are being explored and no decisions have been made about whether it will be delayed or not.

When to get a test - PM's plea

If you have visited Auckland in recent days you should remain vigilant for any symptoms and there is no requirement for self-isolation at this stage, Ardern said.

"If you have any symptoms then do get tested. But, if you have no symptoms and you don't work in [managed isolation facilities] or at the border and you're perfectly healthy then don't," Ardern said.

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Extra precautions are needed to look after elderly Kiwis so all aged care facilities will close their doors, she said.

Staff won't work across multiple sites, Ardern said.

"i realise how incredibly difficult this will be for people who have loved ones living in these facilities," Ardern said.

"We are taking a rapid response to break the chain of transmission," Ardern said.

"We have the systems in place to stamp out the virus and stop it spreading."

The fact the family visited Rotorua reinforces why the whole country has moved to alert level 2, Ardern said.

Ardern said it's primarily casual contacts being assessed in Rotorua at this stage.

"In order for us to trace where this outbreak stems from it is really important we increase the number of people being tested, but that doesn't mean we want to test people across Auckland who have no symptoms," Ardern said.

Healthline has received over 2000 calls since last yesterday.

If you have general questions please don't call Healthline, Ardern said.

"Wash your hands. Stay at home if you're sick and get a test if you're symptomatic."

"I know how hugely frustrating this situation is for every one of our team of 5 million," Ardern said.

"Please as always, stay kind look after one another and please stay tuned as we update you."

Cover up - when to wear a mask

"If you are in Auckland please cover your face if you leave your home," Ardern said.

"A mask or any face covering such as a scarf or bandana will suffice. While we are not mandating their general use at this stage we're strongly encouraging their general use in the Auckland region."

Countdown and Foodstuffs have supply. 5 million of the Government's general supply is being distributed across the country as well.

If your supermarket doesn't have any available you can fashion your own at home.

Masks must be worn on flights leaving Auckland. That is only place masks are mandatory.

The rules for Aucklanders under alert level 3

Aucklanders should continue to stay in their household bubbles. Only the children of essential workers can go to school. Visitors can't be invited into homes. Physical distancing must be used when out on essential trips like to pharmacies or supermarkets.

Businesses can trade without physical contact with customers, but customers can't enter premises.

Supermarkets, dairies, petrol stations can have customers. Retail is possible through delivery or click and collect