Daily incidence

As can be seen in this graph (Figure \ref{the-first-plot}), the trend of the cases grew rapidly till 2nd April, then there was a plateau, and then the number of cases steadily decreased starting 3rd April. In the absence of any intervention, the number of cases would have gone upward. New Zealand started “lock down” or level 4 of the intervention to “eliminate” the infection in and around 25th March, 2020. This meant that the effects to reduce the new number of cases even with increased surveillance and relaxed criteria took about 10 days to take effect. Note that this roughly or on average the time it takes an infection to manifest from first infection. This suggests that despite limitation in the number of tests being conducted, the tests were on track to identify and estimate the true number of cases.
Here are the details of these parameter estimates as of now: