The death toll from the 6.3 magnitude earthquake that hit the southern New Zealand city of Christchurch has risen to 75.

New Zealand Prime Minister John Key declared a national emergency and confirmed at a Wednesday press conference that the number of dead had risen by 10 from a day earlier.

"Today all New Zealanders grieve for you Christchurch," Key said, TVNZ reported.

"On behalf of the government, let me be clear that no one will be left to walk this journey alone. New Zealand will walk this journey with you. We will be there every step of the way," he said.

Christchurch Mayor Bob Parker said about 300 people are listed as missing following Tuesday afternoon's quake, but he added that the number of people trapped in buildings is not known.

The city's central business district was ordered evacuated early Wednesday afternoon over concerns the tallest building in Christchurch, the 26-storey Hotel Grand Chancellor, might collapse.

Rescue crews, some with sniffer dogs, have pulled 120 people alive from the debris and rescue teams were focusing efforts on six downtown sites where many people were trapped, including as many as a dozen visiting Japanese students.

Crews can't use equipment they would normally use to prop up buildings and secure slabs of concrete and instead are having to do much more by hand.

Some survivors were able to send text messages or make phone calls from under the wreckage.

Efforts to find trapped victims on Wednesday afternoon local time were focusing on the Pyne Gould Corp. building, where rescuers believe as many as 50 people may have survived the earthquake, the New Zealand Herald reported.

One woman was pulled from the building about 25 hours after the earthquake hit.

Need for drinking water

Christchurch residents were ordered to evacuate the city centre following the quake. Thousands of people spent Tuesday night in makeshift shelters, Andrew McKie of the Red Cross told CBC News in an interview, adding his agency is helping to provide drinking water because the water supply is compromised.

Canadian contacts

Friends and relatives seeking information on Canadian citizens believed to be in the affected areas should contact the Emergency Operations Centre at the Department of Foreign Affairs and International Trade by calling 1-800-387-3124 or 613-996-8885. They may also send an email to

"The government is willing to throw everything it can in the rescue effort," Deputy Prime Minister Bill English said. "Time is going to be of essence."

In Canada, the Department of Foreign Affairs said it had no reports of any Canadians affected by the earthquake. Speaking to reporters in Victoria Tuesday, Prime Minister Stephen Harper said the situation was affecting him personally because he and his wife Laureen have friends there whom they have not been able to contact since the quake hit. Laureen Harper also lived there for a time when she was younger.

Harper said he has been in contact with Prime Minister Key, and pledged assistance. However, Harper didn't say anything specific about what Canada would contribute.

Canadians in the quake

Olivia Harris of Vancouver Island, who is studying radiology at a Zealand Hospital in Christchurch, was doing a phone interview with CBC News when a powerful aftershock hit Tuesday.

"Oh my God, there's a huge one again. … I'm right in the middle of the road so nothing can really fall on me," Harris said, adding that at the hospital there was pandemonium.

"The influx of patients just coming in … such a fast rate. There was doctors rushing into the hospital saying, 'I'm a doctor, how can I help? How can I help?'"  

Eventually, Harris said, she made her way home but was too frightened to sleep inside, so she spent the night camping on her lawn.

Eleisha McNeil, formerly of Toronto, said on Tuesday that her street was a "sea of mud and water that's bubbled out of the ground" and that she felt some aftershocks.  

She was home with her husband and baby when the initial quake hit Monday, bouncing her all over the house.

"The noise was astounding. Everything that could fall down, did fall down."

McNeil said that New Zealand Television is reporting the death toll could rise to 400.

"It is a just a scene of utter devastation," Prime Minister Key told TV One News in Christchurch. "This may be New Zealand's darkest day."


Top of cathedral collapses

The spire of downtown Christchurch Cathedral collapsed into a central city square.

Video footage showed some multi-storey buildings collapsed in on themselves, and others with walls that had collapsed into the streets, strewn with bricks and shattered concrete. Police said two buses were crushed in the city centre by falling buildings.

Sidewalks and roads were cracked and split, and thousands of dazed, screaming and crying residents wandered through the streets as sirens blared.

Groups of people helped victims clutching bleeding wounds, and others were carried to private vehicles in makeshift stretchers fashioned from rugs or bits of debris.

The quake first hit at 12.51 p.m. local time, according to New Zealand's GNS Science. It was centred at Lyttelton, N.Z., southeast of Christchurch, at a depth of five kilometres.

The quake caused 30 million tonnes of ice to break off the Tasman glacier. It's the biggest glacier in New Zealand, about 200 kilometres from Christchurch.

Aftershocks were continuing, the New Zealand Herald reported. They included a 5.7-magnitude aftershock at 1:04 p.m. at a depth of six kilometres, 10 kilometres south of Christchurch.

The city's airport reopened Wednesday for domestic flights. Christchurch Hospital remained open but was damaged, the Press reported.

People working in the centre of Christchurch interviewed by Sky News New Zealand said the quake was much worse than last year's.

Because the quake occurred at lunchtime on a busy Tuesday, many more people were hurt. The Sept. 4, 2010, earthquake, registering at 7.1 magnitude, occurred on a weekend, and since then, Christchurch has been hit by hundreds of aftershocks, causing extensive damage and a handful of injuries, but no deaths.


New Zealand sits on the Pacific Ring of Fire, an arc of earthquake and volcanic zones stretching from Chile in South America through Alaska and down through the South Pacific, which records more than 14,000 earthquakes a year. (CBC)

With files from The Associated Press