Officials say Wairoa has had the worst of the storm battering the East Coast.

States of emergency have been declared in the Wairoa District and Heretaunga Ward, with torrential rain closing roads and caused hundreds of evacuations overnight.

Heavy rain warnings have lifted for Tairawhiti, but continue until 11pm in Hawke's Bay.

Wairoa is cut off by slips - and the Emergency Response Minister Mark Mitchell will be flying in by helicopter.

He's unlocked $100,000 each for the mayoral funds for Hastings, Wairoa and Tairawhiti.

Mitchell says people in Wairoa have had to leave flooded homes.

"I know that the memorial hall is filled with people, the number I was given was about 100 people. Houses have been evacuated - it's the swell that's made the big difference."

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