Third of quake-hit city faces demolition

The news came as Christchurch mayor Bob Parker assured relatives of the missing that every effort was being made to locate any remaining survivors.

British High Commission spokesman Chris Harrington said he believed at least seven UK nationals were on the missing list.

"There are around 16 to 20 people missing in the city's cathedral and there is a chance that some will be tourists," he explained.

"Rescue teams are slowly starting to dismantle the rubble and lift the masonry off the collapsed central tower to look for life."

The commission stressed that the UK was "only too willing to help".

UK High Commissioner to New Zealand Vicki Treadell added: "With New Zealand and Britain being such close friends, this is an opportunity to support and assist each other at this time of crisis."

Meanwhile, British families waiting for news of their loved ones caught up in the disaster were clinging to hopes they would be found alive.

Jo Morley, 44, whose brother Phil Coppeard from Bury St Edmunds in Suffolk is among the missing Britons, was taking comfort from the miraculous tales of survival following the Haiti earthquake in January last year in which an estimated 316,000 people died. She said: "Of course you still hope, as anybody would do. That's what we have to think."

Chartered accountant Coppeard, 41, emigrated to New Zealand in November with his wife Suzanne Craig and was doing a Masters degree in economics at the University of Canterbury. He was travelling into town on a bus when the earthquake struck.

Christchurch police superintendent Russell Gibson said rescuers were not completely ruling out good news.

"I talked to experts who say they've worked on buildings like this overseas and they get miracles. New Zealand deserves a few miracles," he said.But families have also been warned to prepare for the "worst type of news", with New Zealand authorities admitting they expected the death toll "to steadily rise" over the weekend.

Two Britons have been confirmed to be among the dead, but that number is expected to grow as the process of identifying the bodies speeds up.

British victim Gregory Tobin, 25, a chef from Tadcaster, North Yorkshire, had been on an around-the-world trip and was believed to have been working temporarily at a garage in Christchurch when the quake struck. The identity of the other British victim, also male, has not been confirmed.

Up to 120 people are also believed to be missing in the Canterbury TV building, where dozens of foreign students from an international school were believed to be trapped.

Prime minister Key also asked that the whole country observes two minutes' silence from 12.51pm on Tuesday, exactly one week after the magnitude-6.3 earthquake, as a sign of respect for its victims.

The prime minister also met families whose loved ones remain missing.

"They're full of fear because they recognise that a significant period of time has lapsed," he said.

"Some of them had their loved ones in the CTV building, and on the best advice we can possibly have, we don't think it's possible that anyone could have survived what has taken place at that building.

"But they also hold on to the hope that there's a chance that somebody in one of the other sites can come out alive."

On the outer edge of the central district, Brent Smith watched in tears as workers demolished the 1850s-era building where he lived and ran a B&B and where antique jugs and a precious Victorian bed were reduced to shards and firewood. His daughters hugged him, also weeping.

"You don't know whether to laugh or cry. I've been doing more of the latter," he said.