Parts of Christchurch to be abandoned – PM

Parts of Christchurch will have to be abandoned and up to 10,000 homes could be demolished as a result of last month's earthquake, according to Prime Minister John Key.

Earthquake Recovery Minister Gerry Brownlee previously told NZPA early estimates suggested 100,000 homes could need repairs while 10,000 could have to be rebuilt.

Prime Minister John Key has confirmed those numbers and said the Government was working to identify which homes would have to be demolished.

"There will be some homes that can not be rebuilt and, as a result of the second earthquake, potentially, some sections and some areas of Christchurch which will need to be abandoned," Mr Key said.

"We will have to present other alternatives for people to live in because the land has been so badly damaged we can't fix it, certainly not in a reasonable timeframe."

Those areas could be limited to streets, but in some cases could be larger, he said.

"The liquefaction damage from the second earthquake is so great, and the land damage, the early indications are, that it is so significant we can't remediate it in any timeframe."

Mr Key said one possibility for residents in those areas was a cash offer.

"The second option is 'here is a sub-division and you can choose a site and maybe a building plan that's commensurable with the insurance model you have'."

Mr Key said Housing New Zealand and the Department of Building and Housing were looking at a range of modular housing options, but that currently there was more temporary accommodation available than people were taking up.

"There are other options for people, many people don't necessarily want to move out of their homes despite the fact that there are no basic infrastructure services there."

Mr Key also announced that a provincial public holiday and a national memorial service would be held on March 18.

Two minutes' silence would be observed from 12.51pm, the time the deadly magnitude-6.3 quake struck on February 22.

The death toll from the earthquake remains at 166, with an expected final toll of more than 200.

More cordons in the city are to be lifted this week, improving public access to the CBD.

The city has been divided into four green zones where restricted access will be allowed, and a red zone closed to the public.

Zones one and two to the east and west of the city centre have opened and zone three, to the north, would reopen to residents and business owners on Thursday, and to the public on Friday.