New Zealand will lift coronavirus restrictions across the country on Sept 21, except in its biggest city, Auckland, which is the epicentre of a second wave of infections, Prime Minister Jacinda Ardern has said.

Ardern said Auckland's restrictions would be reviewed next Monday. She also said the government would immediately ease all physical distancing requirements on planes, a boost for Air New Zealand, which has had to limit passengers on its planes for months.

“I know this change will make a real difference to Air New Zealand and those parts of the country seeking increased numbers of visitors,” Ardern said in a news conference in the South Island city of Dunedin, where she is on an election campaign trip.