Scientists are sounding the alarm behind closed doors at the Ministry of Health over New Zealand's readiness to move to more relaxed pandemic settings.
Their concerns centre on the ministry's ability to rapidly trace close contacts of Covid-19 cases and an outdated surveillance system - described by one insider as a "dinosaur".
If those weak spots cannot be urgently addressed, it could significantly affect the Government's confidence in moving to alert level 3 when Cabinet considers the issue on Monday.
The ministry was provided a report on the shortcomings in its contact tracing last Saturday, but is yet to release it.
The report, by University of Otago infectious diseases physician Ayesha Verrall, was understood to be damning of the ministry's tracing approach at the time of the audit.
The delay in publicly releasing it indicates the ministry is still scrambling to improve its tracing capabilities before Monday's Cabinet meeting.
Director-General of Health Ashley Bloomfield said on Wednesday he had received Verrall's report and officials were "furiously" responding to its recommendations.
He said it would be given to ministers in the next 24 hours and then made public.
However, the Ministry of Health said last night that there was no update on when it would be released.
Prime Minister Jacinda Ardern said on Wednesday there was discussion among officials about whether the report should be released before the Government responded to its recommendations.
"But then immediately the question becomes 'What have we done?'. So we're putting [them] both out at the same time.
"I imagine fairly soon after the ministers having received it we will put it into the public domain."
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Verrall did not respond to a request for comment.
When community transmission was first confirmed in New Zealand, she said the ministry needed to rapidly scale up contact tracing to 1000 people a day. At the time, it was tracking 50 people a day.
As of April 5, the ministry had scaled up to 700 people a day, backed by doubling in funding to public health units and the establishment of a National Close Contact Service (NCCS) in Wellington.
There are further concerns about surveillance testing, which relates to broader collection of information to see where coronavirus is present in the population or among certain demographics.
These have been raised internally by a group of scientists who have been seconded into the Ministry of Health from their academic roles to help with the Covid-19 crisis.
Many of their concerns relate to the outdated system used by the Institute of Environmental Science and Research (ESR) to manage the data about Covid-19 cases - referred to by one source as a "dinosaur". There are fears the system cannot work quickly enough to isolate positive cases and stop transmission.
Another expert told the Herald the way the data is structured in the system is one of the barriers to properly mapping and tracing clusters. It requires manual work to get the information out, rather than being exported in a structured way.
This is on top of concerns already raised by external scientists about the way New Zealand's devolved health system - the district health boards and the public health units - feed the data into that system. One scientist this week said some of the information is still shared by fax machine.
According to a blog post by six University of Otago academics last week, there are four key areas of surveillance and testing which need to be in place if New Zealand is to minimise its time in lockdown.
Two of those measures - testing of moderate and severe cases, and testing of symptomatic cases - are already underway.
The third measure, testing of asymptomatic people who are at higher risk of exposure, began this week. People at shopping centres in the Waikato, Christchurch, Queenstown and Auckland were randomly tested to get a broader picture of the virus' potential spread.
One of the academics behind the blog, public health researcher Nick Wilson, said much larger samples in many more regions would be needed "for adequate confidence to achieve the elimination target".
The fourth measure is testing which determines whether the virus has been eliminated, and is most commonly done through sewage systems. This is only the pilot stage in New Zealand.
"I think that New Zealand needs to be very cautious about reducing restrictions," Wilson said.
"Given that we know that this pandemic virus is very infectious, that there is probably around 50 per cent of cases that have no symptoms. There is much about it that we don't know."