A chunk of central Christchurch reopened to businesses and the public this morning, but authorities have warned people to be cautious as aftershocks from Saturday's devastating earthquake continue.
Civil Defence warned that the area could be hit by another big aftershock after residents were kept awake overnight by a series of strong aftershocks.
The aftershocks, ranging from magnitude 3.1 to 5.4, that shook the city overnight meant the inner-city cordon that had kept the public out of the city centre could not be reduced to the extent initially planned, Christchurch City Council rescue manager John Buchan said.
The aftershocks damaged the welfare centre at Burnside High School which was closed this morning. People were being relocated to the main welfare centre at Addington Raceway.
There was an increase in the number of people staying in the welfare centres overnight. Linwood welfare centre hosted 105 people, Addington another 145 and 71 people stayed at the Burnside welfare centre.
The aftershocks during the night also caused new cracks to open in the domestic terminal at Christchurch Airport and travellers on domestic flights were leaving from the international terminal.
Mr Buchan said that much of the inner city cordon would be relaxed at 8am, with Cathedral Square and Colombo Street reopening.
"This is a major step toward freeing access to the city," Mr Buchan said.
There would be full access for building owners and the public in this area, except where damaged and unsafe buildings had been taped off.
"We do, however, urge that people exercise caution as aftershocks continue," Mr Buchan said.
The area that remains cordoned off is bounded by Worcester St, St Asaph St, Colombo St (with the side streets to its east remaining out of bounds) and Madras St.
"We are working to reopen these areas, but it's difficult where buildings have been extensively damaged and have yellow or red placards," Mr Buchan said.
"It will take a few days to work through these areas and many buildings will remain taped off.
Authorities had intended to move the northern boundary of the cordon one street further south of Worcester St to Hereford St, but that was revised after strong aftershocks raised concerns about the safety of a damaged multi-storey building in Hereford St.
The aftershocks included one with a magnitude of 5.2 shortly before 11:30pm, one of 5.4 soon after, and another of 5.4 around 3:30am today.
The council said its staff, the Fire Service and Urban Search and Rescue had dealt with thousands of calls about houses and assisted homeowners with securing their houses, removing chimneys and ensuring access to properties.
All 678 buildings in the CBD were inspected and buildings were affixed with either a green, yellow or red placard. Green means safe, yellow means limited access and red means the building is unsafe. Sixty nine percent of buildings have a green placard, 26 percent a yellow and 5 percent a red.
Civil Defence said less than 5 percent of city properties were without water.
Staff repaired 100 leaking water pipes, returning water to 21 streets, with it still cut off for 38 streets.
Fewer than 1000 power customers remain without power.
Bus services are resuming this morning, with the exception of the inner city shuttle, while most schools are expected to reopen tomorrow.
About 250 people stayed in welfare centres last night.
The aftershocks kept the region tense yesterday, as people came to terms with the damage, with the Government estimating 100,000 homes were damaged.
A street in suburban Bexley was evacuated yesterday because the sections were covered in deep layers of silt.
There were health concerns too, with two families in a welfare centre reported to have contracted gastroenteritis, though it was not known whether they had caught the stomach bug before the quake or after it.
But health authorities reinforced the message that people should continue to boil drinking water for at least three minutes.
Prime Minister John Key will travel to Christchurch this afternoon to meet the region's mayors and inspect damage.
He said yesterday the Government was paying $5 million in to the mayoral relief fund, to help those suffering hardship. The Warehouse, ANZ Bank, BNZ, Westpac, Fonterra and Fletcher Building promised $1m each towards flood relief efforts.
The Earthquake Commission has received 15,000 claims already.
NZPA