Residents of more than a dozen low-lying Coromandel Peninsula coastal communities are being told to get out immediately.
The Thames-Coromandel District Council says many communities are now being affected by king tide flooding and people need to get out while they can.
Fire crews are going door-to-door in the holiday hotspots helping evacuate people to welfare centres as the situation becomes urgent.
Affected communities are Whitianga, Whangamata, Tairua, Pauanui, Matarangi, Hahei, Whangapoua, Kennedy Bay, Cooks Beach, Kuaotunu Beach, Opito Bay, Onemana, Whiritoa, Tapu, Coromandel and Colville. Just before 12.30pm Thames firefighters started to help evacuate low lying areas of the township.
Civil Defence welfare centres have been set up across the peninsula.
A defence spokesperson said people in beachfront properties or estuaries and other low-lying areas that have flooded in the past during high tides needed to leave and stay with friends or family on higher ground or go to an emergency shelter.
It is not known how many people have been evacuated.
Rain is falling steadily in Whitianga as Cyclone Cook nears.
However, there are surprising volumes of traffic on the road between Tairua and Whitianga this morning, despite requests from authorities to clear out.
All rivers and streams are already swollen and a few farms, still saturated from last week's storm, had a bit of surface flooding.
In Whitianga, police had evacuated homes along the waterfront as a precaution.
The rain began falling steadily about 11am.
Locals making the most of the situation were friends Jay Piper-Healion, Tangaroa Lewis and Julian Everth.
Everth was behind the wheel of a motorised go-kart towing Lewis and Piper-Healion behind on boogie boards.
One person was in the ocean, trying to catch a wave in the rough conditions.
Although it's wet and windy, it appears the worst is yet to come.
Residents needing a safe place should go to:
Coromandel St John Ambulance - 355 Tiki Rd, Coromandel
Whitianga Town Hall - 22 Monk St, Whitianga
Tairua Hall - 210 Main Rd, Tairua
Whangamata Town Hall - 320 Port Rd, Whangamata
Thames Civic Centre - 200 Mary St, Thames
The Fire Service said rural fire crews were helping council officials with the mass evacuations across eastern and western coastlines of the peninsula.
Roads may close as the weather worsens to stop people coming in for Easter.
Thames-Coromandel Mayor Sandra Goudie said the council might be forced to close roads in and out of the district to keep people out and keep them safe.