These measures could include cutting the numbers of essential workers in the workplace, improving protective barriers and increasing mask-wearing - particularly in indoor areas - to combat the highly infectious aerosol-spread virus.
The call comes as Cabinet meets today to confirm the extension of level 4 for Auckland and Northland from 11.59pm on Tuesday. It is expected Northland will remain at level 4 for at least another week and Auckland potentially for two more weeks. The rest of the country moves to level 3 from Wednesday.
The total number of cases in this outbreak now stands at 511, with 83 new cases announced yesterday and 82 on Saturday - the highest two tallies of the outbreak, so far.
Director-general of Health Dr Ashley Bloomfield said authorities expected to see the high number of cases continue over the next few days - largely because of the large number of household contacts and more infectious nature of the Delta strain.
This was neither concerning nor unexpected, he said, but it would be worrying if we started seeing more cases in the community.
Of the 511 cases, 453 cases have been clearly epidemiologically-linked to another case or sub-cluster, while there are a further 58 cases for which links are yet to be fully established.
Importantly the "R", or reproductive, number of the virus had dropped below one, meaning each person on average was infecting less than one other person.
Epidemiologist Dr Michael Baker said it appeared the case numbers were beginning to plateau and it was good news the "R" number was dropping.
"It shows people in Auckland are doing what they need to do to stamp this out. We really got there in the nick of time with lockdown."
However, while not rising exponentially, case numbers were still high and would take a while to stamp out under current settings, Baker said.
"We want to get Auckland out of lockdown as soon as possible. But unless we can suppress transmission more it is looking like they could be at level four for many weeks more."
Importantly, Baker said any points of transmission needed to be closely examined and restrictions around them tightened up.
This could involve reassessing the definition of essential workers, and seeing if any could actually work from home instead.
Other measures would be recognising the aerosol nature of the virus, and tightening up indoor areas with mask use and barriers.
Outside of essential services there should also be close scrutiny of how cases have spread so the public are aware of why extra measures were required.
"If we want to keep the whole country understanding not just what but why, we need that information presented in a clear way."
Each day Baker said the ministry should be explaining as much as it can about how the latest cases have occurred, and what is being done to plug those gaps.
Dr Siouxsie Wiles said staff might need mandatory vaccinations and be required to wear N95 face masks if working in an area where it was impractical to keep windows or doors open or ventilation can't be retrofitted.
The microbiologist said physical distancing, perspex barriers and even low-grade face masks weren't good enough at stopping Covid-19 in some enclosed spaces.
"The big risks are indoor spaces at the moment."
University of Auckland Professor of Medicine Des Gorman agreed it looked like our Covid-19 cases were plateauing but everyone, including him, was just guessing.
Speaking to The AM Show this morning, Gorman said the current numbers were consistent with spread within homes. "I can't see any evidence that there is something dire or very worrying going on...the lockdown is almost certainly working."
Suggestions of a stronger level 4 and "doom and gloom predictions" about being locked down until Christmas were unhelpful, he said. If there was no reward for vaccination or staying home, people would be disincentivised to get the jab or follow the rules.
Plans to double the number of contact tracers showed the Government was ill-prepared for the outbreak - but it was "better late than never", he said. "Our contact tracing capacity was nowhere near good enough."
However, level 4 lockdown would make up for the "deficiencies in our public health measures".
Asked whether he was concerned about people potentially spreading the virus while exercising, Gorman said he was at Cheltenham Beach yesterday, and although it was busy everyone was socially distancing and wearing a mask.
It was important that people were able to exercise and maintain their mental health, he said.
He was concerned mental health and diseases such as cancer would be deferred by the lockdown.
University of Auckland Covid-19 modeller Shaun Hendy said with the Delta variant, a lot of people are testing positive after a family member or household member has tested positive.
Speaking to Newstalk ZB's Mike Hosking this morning, he wanted to understand why the Bluetooth feature on the Covid tracer app was not being used. "I'm a little bit surprised by that."
"I do think we need to be taking this lockdown very seriously," he said, adding that it was not inconceivable that we could see alert levels coming down.
Put to him that it looked as if Auckland, at least, would stay in alert level 4 lockdown for a few more weeks, Hendy said it was still difficult to tell at this stage.
"If we start to see numbers dropping sharply this week - so towards the end of the week, if numbers start coming down - then two weeks is not inconceivable.
"We did see the move to alert level 3 in Wellington with cases because they had those cases contained."
"The levels of testing that we've done in this outbreak have been phenomenal and they will give the Government the confidence to move once they see those numbers coming right down."
Hendy said it was always a risk when essential workers came together.
The Ministry of Health has been unable to provide clear data about the nature of the new cases during lockdown, importantly how many have been infected within their household bubbles and how many infected in the community. The Herald has been asking for this information since lockdown began.
When asked on Sunday for these figures, Ardern was not able to give a clear answer but said there were 53 "mystery cases".
She said more than 75 percent of the positive cases reported yesterday were contacts of known cases and more than half of all cases yesterday were household cases, showing how infectious Delta was.
A total of 25 people had exposure events outside of the household and there tended to be essential work sites that were not customer facing.
There had also been transmission at four essential workplaces between staff members in non-public-facing roles.
Overall there were at least 73 essential workers infected during this outbreak, though it was not clear how many had been infected since lockdown began and how many had passed on the virus to others.
In New South Wales, experiencing the worst outbreak in Australia with more than 1200 cases and six deaths on Sunday, many Delta cases spread through essential workers.
Ardern said they were looking closely at the rules around essential workers.
"We've asked for further analysis of the nature of these workplaces, so we can assess whether our level 4 rules on who is operating is being adhered to, and whether our public health protocols for those businesses that are operating are fit for purpose.
"This may not be a problem with the rules, say, on the factory floor but what is happening perhaps before or after shifts, or even during break times.
"We're looking at all of this in more detail, if we need to tighten up our restrictions further, we will."
Ardern has also acknowledged the ongoing positive cases, combined with lockdown, could be hugely unsettling, impacting on mental health and stressed that support was available for anyone who needed it.
"It was okay to feel frustrated and there were places to go for help."
She said there had been a spike in calls to Youthline since the last lockdowns and an additional $1m would be put into increasing support, particularly for rangatahi in Auckland and Northland.
There was also targeted assistance for Pacific communities, which had borne the brunt of the outbreak so far, she said, and assistance for those struggling to access food.
An extra $7m was announced yesterday to assist organisations with things like distributing food parcels and welfare packages.
Meanwhile, Deputy Prime Minister Grant Robertson said New Zealand could take over other OECD countries by the end of this year if Kiwis keep up the level of vaccination rates the Government has seen so far this lockdown.
There were nearly 80,000 people vaccinated on Saturday, and over 90,000 the day before.
Robertson said New Zealand wouldn't run out of vaccine. "We won't run out of vaccine. We have orders coming and by the end of October we will have everything in terms of the vaccination that we need."
