After weeks of urging by public health experts and government wrangling, the country's Health Department has settled on a definition of elimination of the deadly virus.

New Zealand has followed an elimination policy path since the arrival of the virus, eschewing lighter approaches by countries including Australia.

The Kiwi approach, including a seven-week lockdown, is paying dividends.

On Thursday, health officials announced they had found no new cases of the virus for the 13th straight day, from thousands of tests.

Just one person in New Zealand has COVID-19, an Aucklander currently isolating who is due to be asymptomatic this week, should the virus follow a normal course.

Australia currently has 491 active cases.

However, the final Kiwi case is irrelevant to whether New Zealand has eliminated the disease.

The Ministry of Health now says elimination can be declared 28 days after the last case from a "locally acquired unknown source", or community transmission, has completed their treatment and tested negative.

According to the Ministry, New Zealand's last case of community transmission tested positive on April 29, and was in isolation until May 18.

"As per the definition of elimination, the 28 day period would be counted from that person's exit from isolation," a department spokeswoman told AAP.

That means when Director General of Health Ashley Bloomfield holds his regular daily briefing on June 15 - 28 days from May 18 - he will be able to say New Zealand has eliminated COVID-19.

Of course, a subsequent discovery of another case of community transmission would re-start the clock towards the elimination milestone.

The date has symbolic meaning but Dr Bloomfield said it wouldn't stop the government's ongoing work to prevent new cases.

"Elimination is an ongoing process," he said.

"It may well be there is no domestic on-shore transmission or on-shore infections of COVID-19. It would be great if we reached that point and it's increasingly looking like we are.

"But our elimination strategy is ongoing because we clearly still have measures at the border and a desire to open up the border in a safe way."

University of Otago Professor Michael Baker, whose research, advice and modelling has been relied upon by the NZ Government through the COVID-19 crisis, has been calling on the government to provide the official elimination definition.

Dr Baker said if New Zealand reached the definition, it would be a "great achievement".

"We are not the top performer in the world, we often say Taiwan is best. They're now at 56 days since their last case.

"But New Zealand and Australia are top in the OECD for mortality which is a huge achievement for both countries."

Iceland (with two active cases) is also close to a NZ-style elimination.

Australian Associated Press