The Health Minister says there is no fixed date by which it will be known if the nationwide lockdown needs to be extended.
Previously Prime Minister Jacinda Ardern referred to April 6 as being the day by which we might know if we were "flattening the curve" of the spread of coronavirus and find out if the lockdown would have to be extended or not.
But Health Minister Dr David Clark says it's impossible to draw a line in the sand about when we will know for sure how the country is doing in its fight against COVID-19.
He says there is no "magic number" the Government is looking for before it decides to relax the lockdown measures, but rather that "it's about the trajectory" of the virus' spread.
"I hope that we will only do four weeks but it really depends upon how New Zealanders take part and what we can see in terms of that curve bending," Dr Clark told The AM Show on Wednesday.
"That will be the proof that we need that it's working, that we could step back to a lower alert level."
The country went to alert level 4 on Thursday last week after community transmission of COVID-19 was confirmed. Ardern said at the time the lockdown would last at least four weeks.
All non-essential businesses have been shut during the lockdown and Kiwis are allowed out of their homes only to exercise or visit the supermarket or pharmacy.
Although he couldn't give a date when we would know how effective the measures were being, Dr Clark suggested that we would soon have more of an idea if they are succeeding.
"What we are imagining, with the self-isolation period and the incubation that there'll come a point where we'll see people who prior to the self-isolation might have become infected," he said. "So with the self-isolation and social distancing and the measures we've taken going to level 4 we would hope that at that point we start to see a flattening or levelling of the curve, as we see the kick-in effect of the self-isolation measures that people are participating in."
There are currently 647 confirmed or probable cases of COVID-19 in New Zealand, with one person dying as a result of the virus.
Dr Clark says the Government is ramping up testing efforts, but with countries around the world racing to stock up competition to obtain testing kits is fierce.
"We're in a competitive international market for this stuff, but our people have been doing well in securing it," he told The AM Show.
Although access to test kits was a concern early on, it "has never reached a point where we haven't had the test kits available", he said.
In particular reagent - a vital chemical used in the tests - was in high demand, he said, with one supplier saying demand was up 70-fold.
"We have 35,000 complete test kits currently on hand and another 30,000 arriving this week and more next week - so we have the testing capacity," Dr Clark said. "So it's up to clinicians to make the decision about who should be tested."
Health workers are currently able to carry out 3700 tests per day, he said.
According to recently released modelling, the pandemic could lead to as many as 14,000 deaths in the country if significant action - such as the lockdown measure currently in effect - was not taken.
Speaking to Parliament's Epidemic Response Committee on Tuesday, Professor Sir David Skegg, an epidemiologist from Otago University, said the Government needed to do more than just introduce a lockdown if it wanted to eliminate the virus.
"A lockdown on its own is not enough", he said. "It's like pressing the pause button on your device."
He said the Government needed to present a clear, concrete plan about how it aimed to eliminate the virus, or, if total elimination was not possible, have a plan B.
Globally, there have been more than 820,000 confirmed cases of COVID-19, with more than 40,000 deaths.