Dozens of people were homeless in Christchurch on Saturday night and a curfew was in place downtown, after a day of shocks that began when a major earthquake struck at 4.35am.
The 7.1-magnitude quake, centred 40 kilometres west of Christchurch at a depth of 10 kilometres, ripped up roads and sent buildings crashing in the city and surrounding townships like Kaiapoi and Darfield. Nearly 30 aftershocks followed throughout the day.
No fatalities have been reported but two people were seriously injured and many people whose homes are inhabitable are sheltering with friends or family or in specially set-up welfare centres.
Christchurch City Council officials were carrying out patrols to check if residents needed a place for the night.
Parts of the city have been cordoned off and a curfew applies in the city centre till 7am on Sunday. Kaiapoi is also under curfew, and a state of emergency in Christchurch and the Selwyn district will remain in force in the city until at least midday on Monday.
The Director of Civil Defence, John Hamilton, says the situation is under control but they are worried about bad weather forecast for Sunday.
Mr Hamilton says their best advice is for people to stay in their homes if the structure is still basically sound.
Milk tankers filled with fresh water
Three milk tankers filled with fresh water arrived in Christchurch on Saturday night to help out Civil Defence efforts in the wake of the devastating quake.
Federated Farmers spokesperson Conor English, says they're keen to assist Christchurch residents, some of whom are still without power and water.
Mr English says Fonterra redeployed three of its milk tankers - carrying between them 75,000 litres of fresh water - to the city's welfare centres.
He says Federated Farmers has extended an offer to the city's mayor to provide whatever help it can in the coming weeks.
Two Iroquois helicopters from Ohakea are helping with reconnaissance and damage assessment work as required by Civil Defence, and Prime Minister John Key - who flew to Christchurch on Saturday afternoon - says the Army is likely to help with the clean-up too.
Christchurch Mayor Bob Parker told Mr Key that fire is the city's worst nightmare.
Two people seriously hurt
Two people have been seriously hurt. One man, in his 50s, is in intensive care in Christchurch Hospital after being hit by a falling chimney, while another man was cut by glass.
The hospital says it is coping well with an influx of people. It has treated several people with broken bones and others with minor injuries such as cuts and bruises.
The Fire Service says search and rescue dogs have been used to search collapsed buildings, following reports that some people were trapped, but it says no one has been found so far.
St John Ambulance says things were chaotic for it at first. Regional operations manager Chris Haines says they had 16 ambulances working within 30 minutes of the quake instead of the normal four. The service received 687 calls between 4.35am and 10.30am.
Mr Haines says most injuries were the result of falling debris, particularly in the CBD.
Historical hotel unstable
The historic Empire Hotel on London St in Lyttelton was badly hit by the quake and is now considered very unstable.
The district's chief fire officer, Mark Buckley, says the hotel's facade, thought to weigh 20 tonnes, is hanging by a thread, and there has been damage to several local churches and the Harbour Light Theatre.
A St Albans resident says water mains have ruptured in the inner-city suburb and lots of chimneys have collapsed.
The facade of a building in Kilmore St has collapsed, blocking one lane of the road.
Residents of New Brighton and Brooklands are being warned to prepare to evacuate from their homes due to flooding and sewage problems.
Civil Defence says residents should not leave now, but should pack what they will need to move from their homes.
Most urban power back on
The power lines company Orion says electricity has been restored to almost 90% of Christchurch but is proving harder to restore in rural areas.
Spokesperson Roger Sutton says about 95% of rural power users, and 98% overall, should have electricity by Sunday night. It could take four days, or longer, to restore power to all areas, he says.
There was very little damage to transformers and pylons in Christchurch, which made the job there easier, Mr Sutton says.
Contact Energy says gas supply has not been affected, and gas is safe to use, though customers are advised to check that the pipes connected to their homes and appliances are secure, and that gas bottles are standing upright.
St John Ambulance said most houses in the city still had no flowing water on Saturday afternoon.
The water supply at Rolleston southwest of Christchurch is contaminated and sewer lines and water pipes ruptured in Christchurch city. The council advises residents on flat areas of the city to boil water.
Civil Defence controller Michael Aitken says much of the sewage is bypassing treatment stations and going straight into the rivers.
The east is the worst hit area, Mr Aitken says. He is warning people and their dogs to stay away from the Avon and Heathcote rivers.
Canterbury towns affected
Waimakariri District Council is advising Kaiapoi residents to leave town if they can, as it may be a long time before water or sewerage services are restored.
Chief executive Jim Palmer says people should move in with friends or relatives outside the town. He says the council is setting up an emergency centre.
Many houses are damaged, local MP Kate Wilkinson says, streets are cordoned off and community patrols are keeping people out of danger areas.
In Darfield, 45 kilometres west of Christchurch, power cuts closed businesses. Selwyn District deputy mayor John Morten says stock was thrown on the floor of the local supermarket by the quake.
Mr Morten says he's had reports of severe damage to properties in the township of Hororata, 56 kilometres west of Christchurch.
Several small avalanches were triggered on the Mt Hutt skifield.