Domestic borders around New Zealand's largest city Auckland will reopen from Dec. 15 for fully vaccinated people and those with negative COVID-19 test results, Prime Minister Jacinda Ardern said on Wednesday.

Auckland is the epicentre of an outbreak of the infectious Delta variant of the COVID-19 and been locked off from the rest of the country for over 90 days now.

But with more than 80% of Auckland and the rest of country fully vaccinated it was time to open up the ability to travel again, Ardern said at a news conference.

"Aucklanders can now book summer travel and accommodation with confidence and businesses inside Auckland and around the rest of the country can plan for summer travellers,” Ardern said.

Travellers will have to either be fully vaccinated or present a negative COVID-19 test result within 72 hours of departure. People breaking the rules will face an infringement fine of NZ$1,000 ($698.60).

Details about easing international border restrictions will be released before the end of the year, Ardern said.

New Zealand only allows its citizens or permanent residents to enter the country, but the returnee numbers are controlled by limiting the spaces available in state quarantine facilities each week, making it hard for many to travel home.

New Zealand had largely successfully pursued an elimination strategy until the persistent Delta outbreak forced Ardern to shift to a focus of living with the virus with higher vaccinations.

She said the cabinet would confirm on Nov. 29 its decision to move Auckland and the rest of the country into the new traffic-light system, which will end lockdowns and use social distancing and other measures to limit the spread of the virus.

($1 = 1.4314 New Zealand dollars)