That the latest Covid-19 cases had not been using the tracer app was "quite typical" to the rest of the country, says an expert who is calling for a new approach targeting high-risk areas.
While it had previously been reported the three cases were not "regular users" of the app, on Wednesday in Parliament Prime Minister Jacinda Ardern admitted definitively they had not been using it.
"No, they did not use QR scanning or Bluetooth," she said in response to a question from Act Party leader David Seymour.
This was in contrast to the Northland case at the end of January, who had used the app diligently, enabling close contacts to be traced quickly.
But it would seem the latest cases were not alone - with the number of scans the day before they were announced on Sunday dropping to a quarter of peak usage in September.
The app is one of the key tools at the Government's disposal when there is a community outbreak, listing key locations people have visited and enabling others who were there at similar times to be rapidly contacted for testing.
Seymour has been calling for scanning or manually signing in to any premises with the app to be made compulsory - something the Government has so far resisted.
Speaking in Parliament she said one of the issues was enforcement.
"We've been worried about, for instance, business owners feeling like they would have to be the ones to enforce customers scanning before they come in, and there are lots of disincentives for that given it might hurt them commercially.
"So we've been trying to work through those issues, and it's still a live discussion."
Despite the family - a mother, father and their daughter from Papatoetoe, Auckland - not using the app, Ardern said they were confident they had the locations of interest because they'd done interviews, and checked bank statements.
"We have a range of prompts we can use that help jog people's memories of where they've been," she said.
"But we never entirely want to rely on memory ... on bank cards. That's why we ask people to use the app, turn on the Bluetooth and keep scanning - it is really important."
But epidemiologist Professor Michael Baker said it was past time for merely asking.
"We've had months of exhorting people to use it all the time, and clearly it is not working - we need a different strategy."
The latest cases were "no different" to the majority of New Zealanders when it came to using the Covid Tracer app diligently, Baker said.
"Really they are quite typical to the rest of the country, which is the problem."
There are more than two million people registered for the app, but in January the average number of scans per day fell to 465,000.
In the 24 hours up to the cases being announced on Sunday, just 730,000 people had scanned. In the following 24 hours this almost doubled, but was still well below the peak in September last year when 2.5 million people scanned.
However, this would still be capturing a smidgen of movements, with total potential scans likely in the tens of millions.
Baker said rather than forcing people to scan everywhere, it should be mandatory in high-risk locations - indoor environments with poor ventilation, and close mingling.
"So nightclubs, indoor bars, events, restaurants where people are close, places where they exert a lot like gyms, and places where people sing a lot like churches."
Big businesses, including major supermarkets, today voiced their support for such a move.
Many such places also had controlled entry, which would make requiring scanning much simpler than without.
"I think rules-based approaches have worked well so far, I think it feels clear and even-handed, people know where they stand, and even I think appeals to the New Zealand psyche."
As people became more accustomed to scanning in mandatory places, usage would likely increase in other venues, he said.
"You want change to happen voluntarily, but when it doesn't and it is important then you have to mandate it, like helmets or seatbelts. And I think with scanning we have reached a point too where people are familiar with it, and understand the rationale."
Baker said provisions should be made for those without the means for smartphones, over even those who simply did not want to use them.
"Subsidising smartphones could be one approach, which would have massive other benefits in bridging the digital divide, improving digital access and literacy anyway. We are spending a lot anyway, so I think where possible it should be in areas that can have such a lasting legacy."