The centre of Christchurch is to remain shut on Monday as aftershocks continue, causing fresh damage to buildings.
A curfew for the city's centre is also in place for a second successive night after Saturday's 7.1 magnitude earthquake.
And Christchurch is bracing for high winds overnight, which could cause more damage to homes and buildings.
The city's mayor, Bob Parker, says until all areas are assessed, the city will remain shut and businesses will not be allowed to open.
Radio New Zealand's Christchurch reporter says that although power is on in most areas, Civil Defence maintains it is a dangerous area with many buildings unstable.
Search and rescue teams inspected many buildings on Sunday with green stickers going on some to indicate they are good to use while others were condemnded.
However, if those safe buildings are within the cordoned-off area, no-one will be able to enter them.
The city council says the cordon has been lifted in the area bounded by Durham St, Cambridge Terr, Montreal St, Armagh St and Kilmore St.
No businesses in the cordon area will be allowed to open.
All schools in Christchurch, Selwyn district and Waimakariri are to be closed until at least Wednesday, following the earthquake.
All planned surgeries have also been cancelled at Christchurch, Christchurch Women's and Burwood Hospitals for Monday.
Non-deferrable cases will go ahead at all three hospitals, and caesarean sections and inductions of labour at Christchurch Women's Hospital also will continue.
Lines company Orion said on Sunday afternoon it had restored electricity to 95% of its customers.
Areas within Kilmore, Madras, Montreal and St Asaph streets are out of bounds to anyone who does not live there.
In Kaiapoi, north of Christchurch, strong winds are making the earthquake cleanup more difficult, as digger operators battle conditions akin to a dust storm.
Large parts of the town centre and a big portion of the residential area are cordoned off, with at least 20 partly collapsed buildings.
A Resident, Ray Rochford, says the constant flow of sightseers to the town is distressing some locals, who are still in a state of shock.
Substantial damage is reported in rural areas, including Darfield and Hororata.
Waimakariri District Council, which covers Kaiapoi, says the earthquake has damaged river stop-banks and there is a risk of flooding from the region's water ways.
Dozens of displaced people spent Saturday night at three welfare centres set up at Linwood College, Burnside High School and Addington Raceway.
The overnight manager at the Linwood centre, Graham Holloway, said 83 people sheltered there, some because of damage to their homes.
The centres will remain open for people who need short term accommodation, however Canterbury Emergency Management says evacuees will need to make alternative arrangements for the longer term, such as staying with friends or family.
The National Crisis Management Centre says people should call 111 only if it is an emergency.
People needing non-urgent health advice are advised to call the 24/7 Healthline on 0800 611 116.
The Canterbury Chamber of Commerce says employees should put personal safety first before travelling into work on Monday.