A leading public health expert believes rapid antigen testing is required to prevent COVID-19 spreading beyond Auckland's border.
From Tuesday most of the rest of the country was put into alert level 3, while Auckland remains at level 4.
Essential workers are allowed to cross the alert-level border to get to work.
Professor Michael Baker says there are now similarities between leaving Auckland and leaving Australia - and it's time measures were in place.
Queuing up to leave level four are essential workers heading south stacked with goods.
But the threat remains that those leaving Auckland, could be carrying COVID - as well as much needed supplies.
"This is where I think rapid antigen tests actually have a role," Baker told Newshub
Among the current COVID outbreak's 764 cases are 31 that remain unconnected - with the source of their infection unknown.
"As long as we have those cases there is a risk they'll be an essential worker who will drive out of Auckland who will drive to another part of the North Island or maybe travel to the south island for good reasons and they could take the virus there," Baker said.
The oral rapid antigen tests are self-administered.
"I mean this is what is happening in many countries now and these tests are cheap, rapid and good enough to pick up most cases," Baker said.
It's a suggestion Dave Boyce of the NZ Trucking Association says they could live with.
"I don't think drivers would be too worried if they had to self-test but it's just how that process is going to be worked," Boyce told Newshub.
"Certainly our view is if we can get our drivers vaccinated, that will make things a lot better and a lot safer for everybody because they are moving about the country quite a bit."
It's not only those driving across the border who pose a threat.
Reports of a third breach of air travel restrictions - where a non-essential passenger has flown out of Auckland, has brought about changes at the city's airport.
Finance Minister Grant Robertson said on Friday steps had been put in place to stop that happening again.
But none of those steps require passengers to undergo a COVID test.
Even the Director of Public Health skipped that step on a recent trip to Auckland.
"No, I did not have a test either before going or coming back .. I practised full use of masks and PPE and physical distancing," Caroline McElnay said on Friday.
Professor Baker also believes the South Island is nearing the point where it should be in level 2 but warns it may be tighter than last time.
"The virus doesn't care about the one-metre rule or the two-metre rule. an aerosol can travel a big distance and it can stay suspended in the air for some time and infect people so we need a level 2 that's very different from the level 2 we had before."
And that will most likely require a mask.
