Director-General of Health Dr Ashley Bloomfield has explained what "eliminating" COVID-19 means after Prime Minister Jacinda Ardern talked about it on Monday.
New Zealand has made international headlines in the past 24 hours after Ardern said the virus was "currently" eliminated.
Speaking to the media on Tuesday, Dr Bloomfield explained that New Zealand hasn't yet eliminated the virus.
"Elimination is not a point in time - it's not 'we've got to the end of alert level 4, we've eliminated it'.
"It's not something that you can just say 'done and dusted' - it is an ongoing effort."
Dr Bloomfield said New Zealand's elimination goal will continue into alert level 3. The elimination approach focuses on zero-tolerance towards new cases, rather than a goal of no new cases.
He defined the "elimination" goal as "a small number of cases, a knowledge of where those cases are coming from and an ability to identify cases early, stamp them out and maintain strict border restrictions so we're not importing new cases. That's what underpins the elimination goal".
Professor Nick Wilson from Otago University's Department of Public Health says we need a scientific definition of what elimination means and New Zealand currently does not have one.
His interpretation of elimination is "no active cases at all in the country for at least a period of four weeks of extensive testing and other surveillance systems in place”. But this definition should ideally be revised by a joint panel of both New Zealand and Australian scientists to "facilitate a joined up trans-Tasman approach".
Michael Baker, a public health expert from the University of Otago, earlier told Radio New Zealand's Morning Report that "eliminating" COVID-19 had yet to be formally defined.
"I think the concern is that as we reduce that distancing, particularly as we head to level 2, that's when any remaining chains of transmission might suddenly appear, and overseas we have seen unfortunate outbreaks of this virus at that point.
"So it might be that a definition of elimination requires that you see no evidence of transmission at level 2 or level 1, that's where I think if the virus was present we would see it returning.
"But a definition of elimination, for example, wouldn't allow for occasional cases to pop up in the community unexpectedly, because that would suggest ongoing community transmission."
New Zealanders need to be more vigilant under alert level 3 because "we don't have the full protections that a lockdown brings with it", Dr Bloomfield said.
Should Kiwis take their "foot off the pedal", case numbers will begin to rise again, he said.
"We have progressed to level 3, but we are by no means in the clear."
Dr Bloomfield said it would take a sustained effort to eliminate the virus from New Zealand shores.
Earlier on Tuesday, Ardern told The AM Show New Zealand needs to keep moving forward.
"We don't have community transmission of COVID, but that doesn't mean there aren't burning embers of it out there."