UPDATED: There is another case of COVID-19 in managed isolation this afternoon plus the four cases of community transmission announced last night.

Prime Minister Jacinda Ardern and Director-General of Health Dr Ashley Bloomfield are providing an update on COVID-19.

Ashley says there are another four probable cases, these people have symptoms and are linked to the four cases from yesterday. He says these people are self-isolating and are awaiting test results.

Five cases of COVID-19 have recovered so the number of active cases in New Zealand remains at 22.

Ashley says a woman in her 20s who tested positive visited Rotorua from August 8 to 11 while symptomatic.

Based on the information about the visit to Rotorua he says none of the contacts are considered close contacts.

Ashley says the visit to Rotorua had not resulted in a positive test for any of the close contacts of the positive case and her child.

He says the symptomatic family members had visited Waiora Lakeside Hotel, the Skyline Gondola and Heritage Farm and 3D Gallery.

He says they remain confident that level 2 is the right level for Rotorua at the moment.

Over 200 close contacts of the family had been identified by about midday, says Ashley.

He says any employees, contractors or visitors to Americold in Mt Wellington, and Finance Now on Dominion Road - and their households - should remain at home in isolation.

Ardern says at midday today a new public health order also came into effect.

The order provides the legal basis to require people to stay at home, unless they are working in places where it is safe for them to do so.

The order also included two new provisions. It is now mandatory for any business or service to display the QR code for the tracing app at all entry points. Businesses will have one week to comply.

The second new element of the health order is a requirement for people travelling out of Auckland to wear a mask while on a plane.

The Auckland region moved to level 3 at midday today, with the rest of New Zealand moving to level 2 simultaneously. The increased levels will remain for three days until midnight Friday, when alert levels will be reassessed.

EARLIER: Prime Minister Jacinda Ardern and Director-General of Health Dr Ashley Bloomfield will provide a COVID-19 update at 4pm.

Earlier today it was confirmed that one of the four new cases of COVID-19 visited Rotorua on the weekend.

Ashley Bloomfield says a woman in her 20s, who is part of the Auckland family currently in self-isolation, visited the Bay of Plenty town while symptomatic.

He is urging people who visited the region on the weekend, and those around the rest of the country, to be vigilant about their health.

"We are working with the family to found out where they visited. There are testing sites in Rotorua.

There are currently testing sites available in Rotorua (on Vaughn Rd) and Taupo for people in the area, he says.

No members of the family require hospital care at this stage.

The ministry is testing all close and casual contacts of the family that have come into contact with them recently, which the ministry estimates to be 130 people including workplace colleagues.

Three colleagues of the male and his partner are symptomatic and are isolating, says Ashley.

The ministry is using genome sequencing on all those who have tested positive to try and track the source of the virus.

Ashley says they are expecting to test tens of thousands of people in the coming days.