Quake-hit Christchurch braces for windstorm

Christchurch: Earthquake-scarred Christchurch braced for a violent windstorm as intense aftershocks rocked the city on Monday, creating treacherous conditions for rescuers scouring the rubble.

The battered city also faced a new danger when cracks opened in a cliff overlooking suburban streets, forcing more residents to flee their homes in the wake of last Tuesday's 6.3-magnitude tremor.

The death toll from the disaster reached 148 on Monday but police have already said they expect the final tally to exceed 200, with more than 50 still listed as "unaccounted for" in the rubble of New Zealand's second largest city.

A windstorm was forecast to whip through on Monday afternoon, officials said, meaning rescuers searching for bodies and possible survivors would have to retreat from ruins already on the brink of collapse.

"(It) will of course, if you have gale force winds, impact on structures, it will affect rescue operations in the area where we have loose masonry," Mayor Bob Parker said.

"We're hoping the weather won't be as violent, in terms of wind, as it could be, but we need to be prepared."

In the suburb of Sumner, two roads were evacuated and an access road was closed off after cracks appeared in a cliff, threatening to send the rockface tumbling onto streets below.

There were also a series of strong aftershocks, one measuring 4.7, increasing the risk to rescue crews and further jangling the stretched nerves of locals, who have endured two major earthquakes in the past six months.

Tuesday's catastrophic convulsion flattened office blocks, tore up roads and destroyed the spire of the city's landmark cathedral, leaving one third of the downtown area facing demolition.

No survivors have been found since a woman was pulled from a collapsed office building on Wednesday afternoon, although rescuers said they continued to hope for a miracle.

New Zealand Police Association president Greg O'Connor, who has been in Christchurch since the earthquake lending support to emergency workers, likened the city to parts of Britain that were bombed during World War II.

"This is our, probably our equivalent of the Blitz in New Zealand," he told Australia's ABC, his voice choked with emotion.

"Nothing can really give a sense of just how serious this is, because you just can't get a sense of it unless you're here.”

"You have got to be able to hear the noise and see the people and smell to really understand the seriousness of this."

For New Zealand's former premier Helen Clark the city brought back memories of the 2010 Haiti earthquake, which she visited in her role as head of the United Nations Development Programme.

"The building damage I've seen compared with Haiti," told Radio New Zealand on Monday, referring to the massive quake that killed at least 220,000 in the Caribbean island in January last year.

"Let there be no mistake, New Zealand has suffered a tragedy of monumental proportions and it's going to require every ounce of recovery in this country to push through from this," she added following a visit to Christchurch Sunday.

Prime Minister John Key was scheduled to discuss how to rebuild the stricken city with his cabinet on Monday and has already said it must be radically transformed if it is to rise from the rubble, with quake-proof buildings.

The naval ship HMNZS Canterbury was steaming to Christchurch from the capital Wellington on Monday, loaded with emergency supplies including water, fuel and fire tankers and temporary bridges.

Sanitation remains a major problem after the tremor destroyed sewerage infrastructure, with the mayor saying city authorities had been forced to pump raw sewage into the sea near Christchurch's beaches.

"It's not something we enjoy doing but (it's) absolutely essential to get some capacity in the waste water system," he told TVNZ.