The disaster was a major aftershock that came less than half a year after the original magnitude 7.1 quake, which shook the region last September. It centred on the harbor at Lyttelton, about six miles southeast of the city, at a depth of only three miles.
Tuesday's quake was followed by several aftershocks, including a magnitude 5.7 temblor. Liquefaction occurred in several areas of Christchurch, along with telecommunications and power outages, according to the New Zealand Ministry of Civil Defence.
Parts of the city are in chaos with numerous buildings destroyed, rubble strewn across the streets, and rescue teams working hard to find survivors, some of whom are trapped beneath debris and inside damaged buildings.
Prime Minister John Key has flown down from Auckland to Christchurch, and announced the latest news about fatalities on TVNZ television on Tuesday night.
"The death toll I have at the moment is 65 and that may rise," Key said.
"So it's an absolute tragedy for this city, for New Zealand, for the people that we care so much about. It's a terrifying time for the people of Canterbury."
Christchurch Mayor Bob Parker said the outlook is not good, calling it a very black day for the shaken city, according to the Australian Associated Press.
"The prime minister has already released the the first list of casualty figures and I'm dreadfully afraid to have to say that that number is going to rise," Parker said on TVNZ. "I've seen probably 20, 25 buildings of significant size with extraordinary damage, probably total damage to them."
Canterbury District Commander Superintendent Dave Cliff said in a New Zealand police statement that a large number of police staff will assist the search and rescue teams. Major roads to the Christchurch Hospital are open, he said, with contingency plans in place for treating casualties.
Cordon points have been established around the central city and police are urging residents to stay at home and check on their neighbors. Due to pressure on cellphones and telephone systems, people are requested to keep non-urgent calls to the minimum.
