The eye of the storm was 230 km east of East Cape and it still had the power to bring severe weather.
The cyclone brought more than 200 mm of rain and gale-force winds reaching up to 145 km per hour.
"Cyclone Pam is moving southeast and is expected to maintain its intensity, or may even intensify slightly, reaching the Chatham Islands around midday Tuesday. A warning is now in place for severe gales, heavy rain and heavy swells for the Chathams," the MetService weather bureau’s statement said.
Waves of up to nine meters were expected in parts of the region because of the high winds and swells, but these were expected to subside to about three to four meters by midday Tuesday, Xinhua reported.
Civil Defense staff was considering further evacuations from low-lying areas.
Cyclone Pam hit New Zealand after causing widespread destruction across the islands of the South Pacific.
