The tremor measuring 7.8 on the Richter scale hit about 60 miles from Christchurch at just after midnight local time, 11 am UK time.
Latest reports suggest that two people have died after a powerful earthquake in New Zealand's South Island.
The tremor measuring 7.8 on the Richter scale hit about 60 miles from Christchurch at just after midnight local time, 11 am UK time.
Two hours later a tsunami arrived and locals on the east coast were urged to head inland or for higher ground. The tsunami is now said to have receded.
Commonwealth Secretary-General Patricia Scotland said, "I offer my deepest condolences to the government and people of New Zealand and pray and hope the worst is over.
"When something like this happens to one of our Commonwealth family members, it brings home the fragility of human life. At a time like this, we resolve to work together to assist in any way we can.
"I will be going to the high level segment of COP22 climate change conference in Marrakesh next week. This tsunami and earthquake bring into sharp relief the challenges we face as a world.
"We need to work together and that is why I am working with experts to enhance measures to promote regenerative development to benefit our vulnerable countries and small states."
Footage from helicopters and twitter posts from residents show landslides and the damage caused.
Wellington City Council says its inspectors, working with experts, are carrying out rapid checks of buildings to assess the danger to local people.
