People living or holidaying in low-lying areas of Coromandel Peninsula are being asked to evacuate.
The Defence Force has already been sent to the district, and four Unimogs are expected to arrive before 10am.
All communities in Coromandel could be affected by the remnants of Cyclone Cook, which are bearing down on New Zealand today, Thames Valley Civil Defence controller Garry Towler said today.
"Whangamata has been hammered since dawn," he said in a video posted to the Thames-Coromandel District Council Facebook page, adding there had been "substantial flooding" to residential areas in the town.
Mercury Bay and Whitianga had "coastal issues".