As a huge effort ramps up to restore essential services to thousands of people in Tairāwhiti and Hawke's Bay, police hold 'grave concerns' for some reported missing.

Five people have been confirmed killed in the devastation of Cyclone Gabrielle.

In Hawke's Bay, a child was caught in rising water in the settlement of Eskdale, a woman died in a landslide, a body was found on the shore at Bay View, and a body believed to be caught in flood waters was found in Gisborne.

The body of a volunteer firefighter who had been missing in Muriwai, near Auckland, since Monday night was recovered yesterday.

By Wednesday, more than 1400 people had been reported as uncontactable using the police 105 online reporting form, mostly in Hawke's Bay and Tairāwhiti.

While police expect a large number of the reports to be the result of communication lines being down, they confirm they have "grave concerns" for several people missing in the Hawke's Bay and Tairāwhiti areas.

The navy ship HMNZS Manawanui is due in Tairāwhiti Thursday morning with water supplies, and HMNZS Te Mana will sail to Napier to supply Wairoa with water and other essentials.

The Defence Force expects to move a water treatment facility to Wairoa, and a rapid relief team that reached the town on Wednesday will be handing out up to 500 food packages.

Engineers and roading crews are checking bridges and clearing roads throughout both regions.

Prime Minister Chris Hipkins is due to fly to Gisborne Thursday morning in what will be his first in-person look at the scale of destruction from Cyclone Gabrielle.

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