Coronavirus: Why South Island won't drop to alert level 1 despite having no COVID-19 cases

With New Zealand facing a further 10 days at COVID-19 alert level 2, the Prime Minister has revealed why the whole country is facing restrictions and not just Auckland, the epicentre of the outbreak.

In a press briefing on Friday, Jacinda Ardern announced the alert level extension and said while there was "discussion" around allowing the South Island to drop to level 1, it just wasn't practical.

"Keep in mind, of course, there are those in the South who would have good reason to want to travel into the north as well - it's not just one way," she said.

That means the whole country will remain at the same alert level, with Aucklanders being urged to remain vigilant against the virus by sticking to their stricter 'level 2.5' restrictions - no matter where they are.

Ardern said Aucklanders should continue to trace their movements, only gather in small groups and be mindful of their social distancing - plus remember masks are mandatory on flights, public transport and taxis.

"Ultimately we're a very mobile country - people travel a lot and the best protection is just keeping in place those risk mitigations like social distancing and gathering restrictions, in case we see it go beyond [Auckland]."

New Zealand's alert levels will be reviewed by Cabinet on September 14 to see if it is safe to drop down to alert level 1.

There are currently 112 active cases of COVID-19 in New Zealand, 75 in the community linked to the south Auckland cluster, and 37 at the Government's managed isolation facilities. On Friday one more person died, bringing New Zealand's total death toll to 23.