New Zealand stepped up recovery efforts on Thursday after Cyclone Gabrielle left at least five people dead and displaced 9,000 in the country's most damaging storm in decades.

Gabrielle, which hit New Zealand on Sunday before making its way down the east coast of the North Island, cut off entire towns, washed away farms, bridges and livestock, and inundated homes, stranding people on rooftops.

Communication and access to a number of areas remains difficult and surveillance flights are being undertaken to survey the damage and identify those who may be isolated.