Prime Minister Jacinda Ardern says people who have travelled from the Pacific Islands are no longer exempt from the strict 14-day isolation period.
A spokesperson from the Prime Minister's office told Newshub of the updated requirement.
The decision follows the first reported cases of COVID-19 in Fiji and Samoa.
It means anyone who has returned from the Pacific Islands will now be required to self-isolate for a 14-day period.
For example, if a person arrived in New Zealand seven days ago, they would be required to isolate for a further seven days.
The decision comes as the country's borders close to any foreign arrivals.
From 11:59pm on Thursday, only citizens and residents will be allowed to enter New Zealand.