The death toll from New Zealand’s devastating earthquake is expected to escalate, amid warnings it could be “considerably higher” than the 65 casualties already recorded.
Christchurch Superintendent Russell Gibson said more than 100 people could still be buried under rubble following the 6.3-magnitude quake and subsequent aftershocks.
Emergency workers were continuing to focus on rescuing those still trapped.
"There are bodies littering the streets, they are trapped in cars, crushed under rubble," Supt Gibson said.
He added that the focus "had turned to the living", with emergency workers trying to locate people through texts and tapping sounds from beneath the debris.
"We may well be witnessing New Zealand's darkest day...The death toll I have at the moment is 65 and that may rise," New Zealand prime minister John Key told local TV. "It's hard to describe. What was a vibrant city a few hours ago has been brought to its knees."
The 6.3 magnitude quake struck at lunchtime, when streets and shops thronged with people and offices were still occupied.
A Department of Foreign Affairs spokeswoman said it has “general” concerns about 70 Irish people in Christchurch and “serious" concerns about five others. There were an estimated 200 Irish people in the city when the earthquake hit, she said.
Consular staff in New Zealand and the Irish Embassy in Canberra are continuing to liaise with government officials and local authorities.
Rescuers, working under lights in rain, are focused on two collapsed buildings: a financial-services office block whose four stories pancaked on top of each other, and a TV building which also housed an English-language school. About a dozen Japanese students at the school were believed to be missing.
Trapped survivors could be heard shouting out to rescuers from the TV building. Local media say as many as a dozen or more people could still be inside. Relatives of those feared trapped kept a vigil outside the building as rain began to fall.
Christchurch's mayor described the city, a historic tourist town popular with overseas students, as a war zone. "All of our energy tonight is really focused on the need to rescue people," said Mayor Bob Parker, estimating 120 people had been pulled out of rubble or rescued so far.
The quake is country's worst natural disaster since a 1931 quake in the North Island city of Napier which killed 256.
"They are largely crushes and cuts types of injuries and chest pain as well," said David Meates, head of the Canterbury Health Board. Some of the more seriously injured could be evacuated to other cities, he added.
British prime minister David Cameron has issued his “deepest sympathies and condolences” to New Zealand in the wake of a massive earthquake and said the UK would send search and rescue team to help.
All army medical staff have been mobilised, while several hundred troops were helping with the rescue, officials said.
A woman trapped in one of the buildings said she was terrified and waiting for rescuers to reach her six hours after the quake, which was followed by at least 20 aftershocks. "I thought the best place was under the desk but the ceiling collapsed on top, I can't move and I'm just terrified," office worker Anne Voss told TV3 news by mobile phone.
Emergency shelters have been set up in local schools and at a race course, as night approached. Helicopters dumped water to try to douse a fire in one tall office building. A crane helped rescue workers trapped in another office block.
"I was in the square right outside the cathedral – the whole front has fallen down and there were people running from there. There were people inside as well," said John Gurr, a camera technician who was in the city centre when the quake hit.
"A lady grabbed hold of me to stop falling over...We just got blown apart. Colombo Street, the main street, is just a mess...There's lots of water everywhere, pouring out of the ground," he said.
Emergency crews picked through rubble under bright lights as night fell, including a multi-storey office building whose floors appeared to have pancaked on top of each other.
Christchurch is built on silt, sand and gravel, with a water table beneath. In an earthquake, the water rises, mixing with the sand and turning the ground into a swamp and swallowing up sections of road and entire cars. TV footage showed sections of road that had collapsed into a milky, sand-coloured lake right beneath the surface. One witness described the footpaths as like "walking on sand".
Unlike last year's even stronger tremor, which struck early in the morning when streets were virtually empty, people were walking or driving along streets when the shallow tremor struck, sending awnings and the entire faces of buildings crashing down. Police said debris had rained down on two buses, crushing them, but there was no word on any casualties.
The quake hit at 12.51pm (11.51pm last night Irish time) at a depth of only 4km, according to the US Geological Survey.
The tremor was centred about 10km southwest of Christchurch, which had suffered widespread damage during last September's 7.1 magnitude quake but no deaths. New Zealand sits between the Pacific and Indo-Australian tectonic plates and records on average more than 14,000 earthquakes a year, of which about 20 would normally top magnitude 5.0.
The Department of Foreign Affairs has opened a helpline for anyone concerned about family or friends caught up in the earthquake.
Staff at Ireland's honorary consulate in New Zealand and the Irish Embassy in Canberra areliaising with New Zealand government officials, local authorities and the emergency services in Christchurch.
Anyone with concerns regarding family or friends who may be in the Christchurch area can contact the department at 01 4780822 and can also register details on the Department’s travel registration system at www.dfa.ie.
The DFA also activated its Consular Crisis Centre to deal with public queries relating to the earthquake at 01 418 0222.
Agencies