Wellington: Air New Zealand has cancelled all flights in and out of New Zealand's capital Wellington, as the remnants of tropical cyclone Gita pummelled the country on Tuesday.

The national carrier said all flights to the capital would be grounded from 2.45pm local time as weather authorities issued warnings of severe weather and heavy rain and gusts of up to 150km/h.

Air New Zealand has grounded all flights out of Wellington. Credit:AP

Prime Minister Jacinda Ardern told reporters at Parliament that the military had been deployed to areas likely to be worst hit and the country's national Civil Defense office in Wellington was on standby to help local authorities.

"My message still to people is please look out for your local warnings and expect disruption to travel and please just be careful," she said.