The Prime Minister maintains Government planning is well advanced - as New Zealand gears up to face Omicron

Jacinda Ardern says that includes a new way of managing cases - and ensuring essential services can operate in a high-transmission environment.

She says Cabinet has already thrashed out what testing will look like.

Ardern says free tests will be focused on those who are symptomatic, vulnerable, essential workers and close contacts.

She's also announced Northland will join the rest of the country at orange in the alert level system from midnight tonight.