"As I've likened it to before, it's about flattening the curve, or as I've heard some say, instead of a tidal wave, reducing it down to a number of small manageable waves - that is our focus," Ardern said at her post-Cabinet press conference.

Ardern said while the directive currently excludes schools and universities, she said the Ministry of Education will be "working with these institutions to reduce these gatherings as they are able to".

The Prime Minister's announcement came just after it was confirmed Auckland's Polyfest had been cancelled as well as Wellington's Homegrown. Over the weekend, Auckland's Pasikifa Festival was cancelled, as was the March 15 Christchurch memorial service.

Ardern said there will be further guidance issued later in the week to help event organisers determine whether they can mitigate some of the issues around gatherings or if they should be cancelled.

"I know this decision is hugely disappointing," Ardern said. "I'm acutely aware as the Minister for Culture and Heritage the impact this will have on the arts sector, but we are making this decision in the best interest of New Zealanders."

The Royal New Zealand College of General Practitioners is backing the Prime Minister's directive.

"People shouldn't underestimate how effective social distancing - like not going to events - can be in slowing the spread of COVID-19," the College's Medical Director, Dr Bryan Betty, said.

"Limiting public gatherings is a critical way to reduce the spread of COVID-19, which is what we want, especially in New Zealand where we're also coming into winter and our normal flu season."

Finance Minister Grant Robertson will announce the Government's economic response to the global COVID-19 pandemic on Tuesday.