Donna to 're-strengthen' as it moves south - NIWA

After sweeping over Vanuatu's northern islands, and blustering through New Caledonia, Cyclone Donna has downsized to a category one, and is heading for New Zealand.

As it tracks south it is forecast to morph into a low-pressure system to the east of the North Island.

NIWA Weather says Donna will "re-strengthen upon extra tropical transition".

Forecaster WeatherWatch says a high to New Zealand's east could encourage Donna to track closer to the North Island, bringing heavy rain, gale winds and coastal swells at the weekend.