It will take at least a year to rebuild the centre of Christchurch, New Zealand Prime Minister John Key said Sunday as aftershocks continued to rock the city in the wake of a devastating 7.1-magnitude earthquake.

Civil defence officials estimated that more than 500 commercial buildings were damaged by the quake and up to 20 per cent of houses were uninhabitable.

This includes about 90 buildings in the central business district, where police cordons remained in place following an overnight curfew, as aftershocks continued to dislodge masonry and glass from crumbling properties.

About 8,000 residents of inner-city apartments were allowed to remain. Police said they arrested several people trying to get into the area, presumably to loot shops and businesses, during the night.

Teams of engineers moved through the central city assessing which damaged buildings would have to be condemned and which could not be reoccupied until they were repaired.

The only death in Saturday’s pre—dawn quake — the most damaging to hit a New Zealand city since 1931 — remained a heart attack victim, though two people seriously injured by falling debris were still in hospital.

As gale—force winds estimated to reach 130—kilometres an hour during Sunday began to batter the region, civil defence officials urged residents able to make temporary repairs to their damaged homes to act as quickly as possible before it became too dangerous to work outside.

Christchurch Mayor Bob Parker said that power had been restored to about 90 per cent of users, but water supply remained a huge problem with at least 200 reported fractures of underground pipes.

Fearing a major health crisis in a city where the H1N1 swine flu virus was reported to be rampant, authorities warned people to boil all drinking water because of contamination from burst sewage pipes.

Residents remained on edge as more than 30 substantial aftershocks battered the region overnight and Sunday morning, the largest reaching 5.1—magnitude on the Richter scale.

About 250 people spent the night in welfare centres set up for those whose homes were wrecked.

One family including eight children in the rural town of Darfield, which was at the epicentre of Saturday’s pre—dawn quake, spent the night huddled under their dining table fearing an aftershock of similar size, Radio New Zealand reported.

The state Earthquake Commission estimated it would receive 100,000 applications for compensation from victims in the city and surrounding Canterbury province, where a number of small rural towns were badly damaged.

Army units have been put on standby to help, and a state of emergency is likely to remain in place for several days in the city of nearly 400,000 people.

Jon Mitchell of the Canterbury Emergency Management Office urged people to remain in their homes and avoid non—essential travel. Those whose homes were too badly damaged should arrange to stay with friends or relatives for at least the next 24 to 48 hours and possibly longer, he said.

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