At least 128 buildings to be demolished in Chch

At least 128 buildings in Christchurch's quake-hit city centre have to be demolished, Civil Defence says.

It has also revealed 37 will be partly demolished, while 12 will be made safe.

Seven other buildings, including the Grand Chancellor Hotel, are listed as critical. They have been recommended for demolition but officials say there is no time frame for this to take place.

The other six critical buildings are the Rolleston Court apartments, New Zealand College of Early Childhood Education, Community House, BDO Spicers Christchurch, Harcourts Grenadier and Kenton Chambers.

Officials said they were deemed critical based on them being more than five storeys tall, their proximity to other buildings and the risk they posed.

There were fears after the February 22 earthquake that the Grand Chancellor would topple but it has stayed upright.

The total list of 184 buildings includes nearly 70 heritage buildings.

About 100 of the 128 earmarked for destruction have already come down or demolition has already started.

Civil Defence national controller John Hamilton said the list would grow as engineering assessments continued.

"There is a lot of sadness in it, as you would expect, because in many cases these buildings have had a significant place in the life of Christchurch," he told Radio New Zealand.

But it was clear to everyone that some of the buildings could not be saved due to severe quake damage, he said.

"I think it's been a very consultative and a very successful process to get people on both sides of the equation to understand the condition of the building and come to a reasonable and pretty pragmatic solution."

Christchurch Mayor Bob Parker said a new city would emerge from the debris.

"It's very clear that the face of the city is going to be completely and utterly different," he said.

Earlier, lines company Orion said power had been restored to about 60 percent of the central business district within the four avenues.

Most customers without power were within the red zone, which was badly hit by the quake.

Christchurch's power network was under pressure as winter approached and about 5000 Christchurch customers in the eastern suburbs have been hit by power outages in the past week.

Network overloading during colder weather, as well as storms and quake-damaged cables, contributed to the outages.

The outages had increased the fragility of the power network in the area and it was important customers minimised their power use to ease the pressure, Orion said.

The eastern network did not have enough capacity to meet heavy demands for electricity as colder weather set in, it said.

It had begun urgent work on a new substation and temporary 1.5km overhead 66kV line in New Brighton, to replace a damaged Orion substation and make the network more resilient to cope with demand.

The Christchurch City Council has begun work on removing dangerous boulders from Sumner, one of the worst hit suburbs in quake-ravaged Christchurch.

The boulders posed a threat to a critical transport route, Wakefield Avenue, the council said.

Further work is also planned to secure the area above homes along Wakefield Avenue and could take up to six months. The council urged residents to call emergency services immediately if they felt they were in any danger of rockslides or rockfalls.

Meanwhile, police have recovered more than 3280 vehicles since the vehicle operation started on March 10.

However, some vehicles could not be removed as owners had not handed their car keys to police.