Here are the dates she set out:

• 27 February - New Zealanders can travel quarantine-free from Australia

• 13 March - doors open for NZ citizens arriving from elsewhere in the world plus some vaccinated skilled workers and backpackers, all quarantine-free

• 12 April - up to 5,000 international students will be allowed to enter

• In July, the country is expected to open up to non-citizens from visa-waiver countries, including Australia, the USA and the UK

• The rest of the world won't be invited to visit New Zealand until October when Ms Ardern intends to fully open the country's borders

Giving a speech in Auckland, Ms Ardern said that opening "in this managed way balances inflows of travellers so people can reunite and fill our workforce shortages".

It will also "ensure our healthcare system can manage an increase in cases".

The country's "strategy with Omicron is to slow the spread" and "our borders are part of that", the prime minister added.

New Zealand, with a population of five million people, has had about 17,000 confirmed COVID cases and 53 deaths - relatively low numbers compared to other countries.

The country's strict border policies have been a big part of this success, but they have also been heavily criticised for keeping many New Zealand citizens effectively locked out of their own country.

For the past six months, New Zealanders have only been able to return by getting a place in hotel isolation via a government-run lottery, or by qualifying for an emergency place via a small number of categories.

Grounded Kiwis, a group advocating for New Zealanders stuck overseas, said it welcomed the move from quarantine to self-isolation.

"Many people in our network are overwhelmed with emotion right now.

"This moment has been a long time coming, and many Kiwis now see a pathway to going home and reuniting with their whanau (family).

"We believe the 27 February date should apply to Kiwis coming from all countries, as there is not a sufficient justification to delay the new process for those coming from countries other than Australia.

"Many of these individuals have been waiting for months already, are due to start new jobs or university in February, and in many cases are coming from locations with lower levels of Omicron than Australia."

Those working in the tourism industry will also be breathing a sigh of relief on hearing the reopening plans.

According to Tourism New Zealand, tourism was the country's largest export industry before COVID-19, directly employing 8.4% of the workforce.