There are 50 new cases of Covid-19 in New Zealand - the lowest daily total reported in a fortnight.

"We may yet see bumps along the way ... but I remain cautiously optimistic that we are starting to turn a corner," Jacinda Ardern said this afternoon.

Today's 50 cases - four fewer than what was reported yesterday - are made up of 26 confirmed cases and 24 probable cases.

The falling cases come as Kiwi kids gear up to start school from home.

Ardern said term 2 of schools would return next week, but it would look different due to the lockdown.

"We have a role to support you," the Prime Minister said.

Ardern said dedicated TV channels would be among the package to provide lessons for schoolchildren.

Tens of thousands of school students had issues with connectivity and distance learning, she said, and she asked parents not to put too much pressure on themselves.

Ardern said businesses need to prepare for how to operate under alert level 3, and that included a new normal including how to contact trace everyone who came through the door on any given day.

"This is kind of preparation we need businesses to do. Equally for your workforce .. and appropriate social distancing."

Alert level 3 allowed some businesses to be open, but not all, and Ardern said guidance will be provided on who could trade.

She didn't say when those guidelines will be ready.

41 recover in last day, four people in ICU

An additional 41 people with coronavirus recovered in the last 24 hours.

The combined total of confirmed and probable cases in New Zealand since the pandemic began is 1210.

There are 12 people in hospital, including four in ICU, two in a critical condition.

Director General of Health Ashley Bloomfield said there were 4098 tests yesterday, the highest number so far, bringing the total to 46,875.

Stock for tests was about 50,000, he said.

Bloomfield said 20 support and care workers, working in both hospitals and in the community, 17 nurses, seven administrative staff, seven doctors and three medical students with Covid-19.

Bloomfield said priority groups receiving the flu jab should do so as it was classed as essential travel, and practices would provide the proper physical distancing.

Border restrictions hit horticulture workforce

Ardern said the Government's border restrictions meant fewer migrant workers, and 90 per cent of horticultural workers were now New Zealanders.

Many had been repurposed to work in the industry to keep people in jobs, Ardern said.

Many workers were also from the Pacific, and Ardern said she understood their concerns as Cyclone Harold ripped through Vanuatu.

New Zealand has deployed an NZDF P3 Orion this morning to undertake aerial surveillance of the Cyclone Harold damage in Vanuatu.

Foreign Minister Winston Peters also announced $500,000 in funding to help the Government of Vanuatu to procure relief items and assess needs and impacts, and for the release of essential relief items already available on the ground.

Ardern said the Government's aviation support package, worth $600m, was helping to maintain air freight connectivity, and the Chatham Islands now also had their air connection secured.

Air NZ had made 17 flights since Monday last week with high-value exports and returning with goods including PPE.

Ardern said proposals had been received from airlines around the world and the Government was evaluating those.

She asked religious leaders to ensure congregations were not coming together - unless they were virtual congregations.

Ardern said she will not be able to say at this stage whether the lockdown will be lifted, emphasising that "now is the time to stay the course".

Bloomfield said the lab testing by region and ethnicity, as well as the positivity rate, was key in showing any community outbreaks.

Ardern said control of the virus was needed, and the data would help to see which regions may be more likely to be in different alert levels.

Bloomfield said the Ministry was providing an overview of the clusters, and Ardern said the privacy issue with one of the clusters had had an effect on how the date was being publicly presented.

The Ministry of Health has previously published a person's name, and then apologised for that.

Ardern said there was no update yet on the legal advice around the Ruby Princess.

Referring to a person linked to Marist College who was not initially tested despite symptoms, Bloomfield said the person was eventually classified as a probable case and the person was right to persist with trying to be tested.

He said he has asked ministry staff to talk to the health professionals looking after each cluster, including testing people without symptoms to ensure those clusters were being properly ring-fenced.

Ardern said tomorrow she will talk through how clusters were being manged.

Bloomfield said antibody testing kits were being developed and the ministry was watching closely. Such tests can be done more easily than lab tests and results were more rapid. They may also play a part in surveillance testing, he said.

He said contact tracing was "very rigorous" with healthcare workers with Covid-19, and staff have been stood down immediately.

Test rates for Māori

Asked about new data about 13.6 per cent of tests being done on Māori, Ardern said people should reach out for a test and there was no stigma or shame in having Covid-19. "We need to know and we need to help."

She said surveillance testing would help fill the gaps in the regional testing data.

Bloomfield said his back of the envelope calculation on the positivity rate was between 1 and 2 per cent for Māori and Pacific peoples, which was a good sign that there was no undetected outbreak.

Ardern said the Government was mindful of tailoring a public health response for Māori and Pasifika.

Delays for test results

Bloomfield said there wasn't enough information about the loss of smell for it to be added as a specific symptom for people to be tested on that symptom alone.

Asked about people waiting up to a week to have test results returned, Bloomfield said people were told about positive results immediately, and he was aware of reports that negative results sometimes took longer they should have.

"People will be waiting and they'll be anxious while they wait."

He said he had contacted a DHB boss this morning when he found out about a case where the test result took longer than it should have.

Bloomfield said the case definition wasn't designed around community testing, which was part of broader surveillance testing.

Ardern said she had no answer on whether the Warriors might be granted an exemption to compete in the NRL.

She said New Zealand was "stamping it out", but the Government was not focused on creating a model for anyone but New Zealand.