New Zealand would move to regionalised lockdowns, rather than the the whole country in the first instance in the event of re-emergence of Covid-19 cases in the community.
Prime Minister Jacinda Ardern said she was "setting out our plan in the event we have a new case of community transmission of Covid-19 in New Zealand".
"There is limited room for error," she told media this morning.
Ms Ardern said alert level increases could be applied locally, regionally and then nationally.
"The first step, if possible, is locally."
"Covid is now exploding outside our borders and every country we have sought to replicate or have drawn from in the fight against Covid has now experienced further community outbreaks," Ms Ardern said.
"Victoria in particular is a cautionary tale for New Zealand that we must learn from. It appears their current outbreak is linked to a managed isolation facility similar to the ones we run here and that the entire outbreak was seeded by just two cases."
Ms Ardern said the alert level system and framework would remain in place.
"But in the event of cases, rather than apply the framework nationally, we would look to apply our alert level system at a localised or regional level in the first instance."
Ms Ardern said the priority was to control cases with the "least intrusive measures, and over the smallest area we can".
"That means doing absolutely everything possible to avoid the entire country returning to Alert Levels 3 or 4 as a measure of last resort."
Ms Ardern outlined scenarios of cases beyond those caught at the border of returning Kiwis.
That included cases in the community, where the country would remain at Alert Level 1 and strong restrictions would be applied locally in a neighbourhood, town or city.
Another was a large cluster within a region. Testing would increase and alert levels would shift regionally, along with travel restrictions.
"This would mean travel in or out of the city, town or region could be stopped, people in that place asked to work from home, and local restrictions on gatherings implemented."
The final is multiple clusters across the country, which would see a national alert level increase take place.