A dairy operating the one in one out policy during lockdown.

Director-General of Health Dr Ashley Bloomfield has announced four more Covid-19 related deaths in New Zealand.

This brings the country's death toll to nine - six of which involved Rosewood rest home residents being cared for in Burwood hospital, he said.

Prime Minister Jacinda Ardern said the deaths were a sad and sobering reminder to stay the course.

Echoing Bloomfield's earlier comment that New Zealand was past the peak and addressing commentary about "taking the foot off the pedal", she said : "We are successfully over the peak but that is not the same thing as being out of the woods."

POOL VISION Dr Ashley Bloomfield provides the Ministry of Health's daily update.

It was day 20 of lockdown and this was likely to be the most challenging week, she said.

Bloomfield reported 17 new cases of coronavirus, made up of eight new confirmed cases and nine new probable cases on Tuesday.

This brought New Zealand's total number of Covid-19 cases to 1366.

"With four more deaths in the past 24 hours, it's our deadliest day to date," Ardern said.

"We always knew there would be more deaths - even at level 4 - and especially in cases where the virus enters a vulnerable community like an aged care facility."

It was a reminder of how much worse the spread and death toll could have been if the country had not moved into lockdown to break the chain of transmission, she said.

In the meantime, the Ministry of Health would continue to undertake more analysis of the testing done to date, ask DHBs to expand testing again, and further strengthen contact tracing efforts.

While a small number, the cases of possible community transmission were the most important to understand and have under control if the country was to move out of level four with confidence, she said.

"Most New Zealanders understand that now is not the time to let up. We must not squander the good work that everyone has put in over the last 20 days."

Bloomfield was now leading a number of actions in an area where every country had faced vulnerability, she said.

She highlighted his requirement for all DHBs to audit arrangements in aged care facilitates, to ensure compliance with Covid-19 protocols and procedures.

"This should also help identify any issues with supply and best practice use of PPE," she said.

Bloomfield had also initiated a review into aged care facilities where Covid-19 had already been present.

This was in less than 1 per cent of New Zealand's facilities and was "a stark contrast" to the situation in many other countries, she said.

The review would look at Rosewood but also the facilities where containment had been successful.

"It is timely and I do endorse the quick action taken by the director-general on this. It is something I absolutely agree with and support," Ardern said.

Bloomfield said he had sent a message to all DHBs on Tuesday to lower the threshold for testing in the coming week to anyone with respiratory symptoms.

"Our expectation is that cases will maintain to remain low but we want to be double sure that we are finding any cass that could be out there ... a number of DHBs are also using mobile testing."

It was clear the country was now past the peak of new cases under alert level four and the key now was to find where new cases came from, he said.

He would be more confident if the source of recent new cases was found this week .

"If we continue to get reasonable testing rates of people with any symptoms and still not finding additional cases, that will provide us with an even great level of assurance," he said.

There were currently 15 people in hospital and this includes three people in ICU – one each in Middlemore, Dunedin and North Shore hospitals. One of the ICU patients – in Dunedin – remained in a critical condition.

Bloomfield said the deaths that are happening now were the result of infections from a few weeks ago.

The elderly fatalities were "already frail have very low reserves to be able to fight off these sorts of infections," he said.

One death occurred in Wellington and there had been three additional deaths from the Rosewood cluster in Christchurch.

All the Rosewood residents had underlying conditions, he said.

The man in Wellington was admitted on March 22 and had been unwell for some time, he said. It was later reported that the man lived in a retirement village and had recently travelled to Australia.

The deaths announced on Tuesday included: two men in their 90s at Burwood, a man in his 80s at Burwood and a man in his 70s in Wellington.

This was the largest number of deaths reported on any one day in New Zealand and was a sobering reminder of what was at stake with Covid-19, Bloomfield said.

AGED RESIDENTIAL CARE REVIEW

He ordered the review of aged care facilities and later this week he would announce funding for the aged residential care sector to help offset additional costs.

The Ministry of Health has been working closely with the New Zealand Aged Care Association, Care Association New Zealand, district health boards and facilities around the country.

The ministry would develop a plan for an independent review of facility outbreaks, to understand what can change and what procedures can be improved.

DHBs were currently looking at each facility's plans and procedures to reduce risk to staff and residents, including assessing the use of PPE, he said.

The ministry would ensure facilities had access to PPE supply lines and other support.

There were more than 650 aged care facilities nationwide, and there had been excellent care and preparation across the sector, he said.

This was highlighted by the fact that in New Zealand, relatively few facilities are affected compared to overseas.

PPE

Bloomfield expected about 10 million items would be delivered this week, of which 9 million were procedure masks or equivalent. Next week he expect 18 million items.

The national ordering process for DHBs had been stood up on Tuesday to initially distribute masks with other PPE products being added moving forward.

DHBs will be placing the first lot of orders under the new system on Wednesday morning with delivery by the end of the week.

Health and disability service providers could also expect to receive stock by early next week, he said.