The lockdown has now been in place for two weeks.

Kiwis will know two days before the end of the four-week lockdown period whether or not the lockdown will be extended, Prime Minister Jacinda Ardern has announced.

Speaking at the half-way point of the lockdown Ardern emphasised that the month-long lockdown was not going to be shortened, despite rapidly dropping numbers of new cases.

"We will not be moving out of Level 4 early. If we move too early, we will go backwards."

Just 29 new confirmed or probable cases were revealed on Thursday, despite over 3000 tests.

Ardern said within the next week detailed guidance on what "Level 3" would look like would be published. Level 3 is the next step down from the current Level 4 lockdown, and still requires the closure of many businesses.

She said Cabinet would make and publicise a decision about whether or not the lockdown would be extended on 20 April, two days before the forecast end date.

"It is my intention that on the 20th of April, two days before the lockdown is due to finish, Cabinet will make a decision on our next steps. That's because we need to use the most up to date data that we have to make that decision."

"That means, if we are ready to move to Alert Level 3 business we will have two days to implement arrangements."

She said businesses should prepare now for Level 3.

"In the meantime I ask every business to use the time you have to prepare for what every alert level may mean for you. Treat COVID-19 like a health and safety issue. Ask whether it's possible for your business to have social distancing? Can you build in contact tracing tools or mechanisms to keep track of your supply train and customers? Help us get ready as a nation for the marathon we must all run together."

Some regions of the country may move out of lockdown sooner than others.

The Prime Minister said she was proud of how well the lockdown had gone so far.

"In the face of the greatest threat to human health we have seen in over a century, Kiwis have quietly and collectively implemented a nationwide wall of defence," Ardern said.

"You are breaking the chain of transmission. And you did it for each other."