Today, the weekly rolling average of new infections is 1778, down from 2425 cases last Monday, and continues a trend of falling below 2000.
The bulk of the climb-down had occurred over August, when daily numbers fell from more than 7000 to fewer than 2300 by the month's end.
"They're still trending downward at the moment, at a rate of about 20 to 30 per cent per week - so there's not really a sign that they're levelling off into a plateau yet," said Professor Michael Plank of Covid-19 Modelling Aotearoa.
The biggest factor in the decline was likely that the virus was now finding fewer people to infect.
Last month, Plank said at least half of the population has now been infected – and those who hadn't yet had the virus were likely among a minority.
"The proportion of infections that are reported is probably somewhere between 40 per cent and 65 per cent," Plank said at the time.
"It's unlikely to be much less than 40 per cent because at least 40 per cent of all 20- to 25-year-olds have already reported a case."
On the other hand, he said, the reported infection rate was typically less than 65 per cent of the infection rate in routinely tested cohorts such as border workers.
"This means it's likely that at least half of New Zealanders have had Covid-19, although those that haven't probably still represent a significant minority."
Speaking to the Herald today, Plank said a potential drop-off in people getting tested might also be contributing to the falling figures.
"That's possibly happening to some extent," he said.
"But the fact that hospitalisations are also trending downward and falling at a similar rate, I think we can say this drop in cases is a real effect, rather than just a testing artefact."
Of the four deaths reported today, one was from Auckland region, two were from Waikato, one was from Southern.
One was aged in their 70s and three were in their 80s. Of these people, two were women and two were men.
There are now a total of 1915 deaths confirmed as attributable to Covid-19, the ministry said, either as the underlying cause of death or as a contributing factor.
The seven-day rolling average increase in total deaths attributable to Covid-19 is now six.
This comes as Prime Minister Jacinda Ardern has announced that, after living with the traffic light system for nearly a year, it was time to look at whether current settings were still "fit for purpose".
The outcome of the latest review was expected to be announced next week.
Despite the lower case numbers, experts have urged the Government to keep in place core measures like masking in high-risk settings and mandatory isolation periods for infected people.
